diff --git a/app.js b/app.js
index 839067a..34e0bcd 100644
--- a/app.js
+++ b/app.js
@@ -75,6 +75,9 @@ app.use('/ideas', require('./routes/ideas'));
 app.use('/ideas', require('./routes/votes'));
 app.use('/comments', require('./routes/votes'));
 
+// care about ideas
+app.use('/ideas', require('./routes/cares'));
+
 // following are route factories
 // they need to know what is the primary object (i.e. idea, comment, etc.)
 app.use('/ideas', require('./routes/primary-comments')('idea'));
diff --git a/collections.js b/collections.js
index b460560..3fc2ccf 100644
--- a/collections.js
+++ b/collections.js
@@ -130,6 +130,19 @@ module.exports = {
         unique: true
       }
     ]
+  },
+
+  cares: {
+    type: 'edge',
+    from: ['users'],
+    to: ['ideas'],
+    indexes: [
+      {
+        type: 'hash',
+        fields: ['_from', '_to'],
+        unique: true
+      }
+    ]
   }
 
 };
diff --git a/controllers/cares.js b/controllers/cares.js
new file mode 100644
index 0000000..6e2aa8c
--- /dev/null
+++ b/controllers/cares.js
@@ -0,0 +1,86 @@
+const path = require('path'),
+      models = require(path.resolve('./models')),
+      serializers = require(path.resolve('./serializers'));
+
+/**
+ * Middleware to add a care to idea.
+ */
+async function post(req, res, next) {
+  // read data from request
+  const { id } = req.params;
+  const { username } = req.auth;
+
+  const primarys = req.baseUrl.substring(1);
+  const primary = primarys.slice(0, -1);
+
+  try {
+    const care = await models.care.create({ from: username, to: { type: primarys, id } });
+
+    const serializedCare = serializers.serialize.care(care);
+    return res.status(201).json(serializedCare);
+  } catch (e) {
+    // handle errors
+    switch (e.code) {
+      // duplicate care
+      case 409: {
+        return res.status(409).json({
+          errors: [{
+            status: 409,
+            detail: 'duplicate care'
+          }]
+        });
+      }
+      // missing idea
+      case 404: {
+        return res.status(404).json({
+          errors: [{
+            status: 404,
+            detail: `${primary} doesn't exist`
+          }]
+        });
+      }
+      default: {
+        return next(e);
+      }
+    }
+  }
+}
+
+/**
+ * Middleware to DELETE a care from an idea (and other objects in the future).
+ */
+async function del(req, res, next) {
+
+  // read data from request
+  const { id } = req.params;
+  const { username } = req.auth;
+
+  // what is the type of the object we care for (i.e. ideas, comments, ...)
+  const primarys = req.baseUrl.substring(1);
+  const primary = primarys.slice(0, -1);
+
+  try {
+    // remove the care from database
+    await models.care.remove({ from: username, to: { type: primarys, id } });
+    // respond
+    return res.status(204).end();
+  } catch (e) {
+    // handle errors
+    switch (e.code) {
+      // primary object or care doesn't exist
+      case 404: {
+        return res.status(404).json({
+          errors: [{
+            status: 404,
+            detail: `care or ${primary} doesn't exist`
+          }]
+        });
+      }
+      default: {
+        return next(e);
+      }
+    }
+  }
+}
+
+module.exports = { del, post };
diff --git a/controllers/validators/cares.js b/controllers/validators/cares.js
new file mode 100644
index 0000000..9c1749d
--- /dev/null
+++ b/controllers/validators/cares.js
@@ -0,0 +1,8 @@
+'use strict';
+
+const validate = require('./validate-by-schema');
+
+const del = validate('deleteCare');
+const post = validate('postCares');
+
+module.exports = { del, post };
diff --git a/controllers/validators/index.js b/controllers/validators/index.js
index 1aa179e..eb05a12 100644
--- a/controllers/validators/index.js
+++ b/controllers/validators/index.js
@@ -2,6 +2,7 @@
 
 exports.authenticate = require('./authenticate');
 exports.avatar = require('./avatar');
+exports.cares = require('./cares');
 exports.comments = require('./comments');
 exports.contacts = require('./contacts');
 exports.messages = require('./messages');
diff --git a/controllers/validators/schema/cares.js b/controllers/validators/schema/cares.js
new file mode 100644
index 0000000..f44df28
--- /dev/null
+++ b/controllers/validators/schema/cares.js
@@ -0,0 +1,30 @@
+'use strict';
+
+const { id } = require('./paths');
+
+const postCares = {
+  properties: {
+    params: {
+      properties: { id },
+      required: ['id'],
+      additionalProperties: false
+    },
+    body: {
+      additionalProperties: false
+    },
+    required: ['body', 'params']
+  }
+};
+
+const deleteCare = {
+  properties: {
+    params: {
+      properties: { id },
+      required: ['id'],
+      additionalProperties: false
+    },
+    required: ['params']
+  }
+};
+
+module.exports = { deleteCare, postCares };
diff --git a/controllers/validators/schema/index.js b/controllers/validators/schema/index.js
index a681495..c80bc4a 100644
--- a/controllers/validators/schema/index.js
+++ b/controllers/validators/schema/index.js
@@ -3,6 +3,7 @@
 const account = require('./account'),
       authenticate = require('./authenticate'),
       avatar = require('./avatar'),
+      cares = require('./cares'),
       comments = require('./comments'),
       contacts = require('./contacts'),
       definitions = require('./definitions'),
@@ -16,5 +17,5 @@ const account = require('./account'),
       votes = require('./votes');
 
 
-module.exports = Object.assign({ definitions }, account, authenticate, avatar,
+module.exports = Object.assign({ definitions }, account, authenticate, avatar, cares,
   comments, contacts, ideas, ideaTags, messages, params, tags, users, userTags, votes);
diff --git a/models/care/index.js b/models/care/index.js
new file mode 100644
index 0000000..1fd297e
--- /dev/null
+++ b/models/care/index.js
@@ -0,0 +1,94 @@
+'use strict';
+
+const path = require('path');
+
+const Model = require(path.resolve('./models/model')),
+      schema = require('./schema');
+
+class Watch extends Model {
+
+  /**
+   * Create a care.
+   * @param {string} from - username of the care giver
+   * @param {object} to - receiver object of the care
+   * @param {string} to.type - type of the receiver (collection name, i.e. 'ideas')
+   * @param {string} to.id - id of the receiver
+   * @returns Promise - the saved care
+   */
+  static async create({ from: username, to: { type, id } }) {
+    // generate the care
+    const care = schema({ });
+
+    const query = `
+      FOR u IN users FILTER u.username == @username
+        FOR i IN @@type FILTER i._key == @id
+          LET care = MERGE(@care, { _from: u._id, _to: i._id })
+          INSERT care INTO cares
+
+          LET from = MERGE(KEEP(u, 'username'), u.profile)
+          LET to = MERGE(KEEP(i, 'title', 'detail', 'created'), { id: i._key })
+          LET savedWatch = MERGE(KEEP(NEW, 'created'), { id: NEW._key }, { from }, { to })
+          RETURN savedWatch`;
+    const params = { username, '@type': type, id, care };
+    const cursor = await this.db.query(query, params);
+    const out = await cursor.all();
+
+    // when nothing was created, throw error
+    if (out.length === 0) {
+      const e = new Error('not found');
+      e.code = 404;
+      throw e;
+    }
+
+    // what is the type of the object the care was given to (important for serialization)
+    out[0].to.type = type;
+
+    return out[0];
+  }
+
+  /**
+   * Read a care from user to idea or something.
+   * @param {string} from - username of the care giver
+   * @param {object} to - receiver object of the care
+   * @param {string} to.type - type of the receiver (collection name, i.e. 'ideas')
+   * @param {string} to.id - id of the receiver
+   * @returns Promise - the found care or undefined
+   */
+  static async read({ from: username, to: { type, id } }) {
+    const query = `
+      FOR u IN users FILTER u.username == @username
+        FOR i IN @@type FILTER i._key == @id
+          FOR w IN cares FILTER w._from == u._id && w._to == i._id
+            RETURN w`;
+    const params = { username, '@type': type, id };
+    const cursor = await this.db.query(query, params);
+
+    return (await cursor.all())[0];
+  }
+
+  /**
+   * Remove a care.
+   * @param {string} from - username of the care giver
+   * @param {object} to - receiver object of the care
+   * @param {string} to.type - type of the receiver (collection name, i.e. 'ideas')
+   * @param {string} to.id - id of the receiver
+   * @returns Promise
+   */
+  static async remove({ from: username, to: { type, id } }) {
+    const query = `
+      FOR u IN users FILTER u.username == @username
+        FOR i IN @@type FILTER i._key == @id
+          FOR v IN cares FILTER v._from == u._id AND v._to == i._id
+          REMOVE v IN cares`;
+    const params = { username, '@type': type, id };
+    const cursor = await this.db.query(query, params);
+
+    if (cursor.extra.stats.writesExecuted === 0) {
+      const e = new Error('primary or care not found');
+      e.code = 404;
+      throw e;
+    }
+  }
+}
+
+module.exports = Watch;
diff --git a/models/care/schema.js b/models/care/schema.js
new file mode 100644
index 0000000..d963502
--- /dev/null
+++ b/models/care/schema.js
@@ -0,0 +1,5 @@
+'use strict';
+
+module.exports = function ({ created = Date.now() }) {
+  return { created };
+};
diff --git a/models/index.js b/models/index.js
index 58013cc..97e269a 100644
--- a/models/index.js
+++ b/models/index.js
@@ -1,6 +1,7 @@
 'use strict';
 
-const comment = require('./comment'),
+const care = require('./care'),
+      comment = require('./comment'),
       contact = require('./contact'),
       idea = require('./idea'),
       ideaTag = require('./idea-tag'),
@@ -22,4 +23,4 @@ const models = {
   }
 };
 
-module.exports = Object.assign(models, { comment, contact, idea, ideaTag, message, model, tag, user, userTag, vote });
+module.exports = Object.assign(models, { care, comment, contact, idea, ideaTag, message, model, tag, user, userTag, vote });
diff --git a/routes/cares.js b/routes/cares.js
new file mode 100644
index 0000000..d0951b1
--- /dev/null
+++ b/routes/cares.js
@@ -0,0 +1,18 @@
+'use strict';
+
+const express = require('express'),
+      path = require('path');
+
+const authorize = require(path.resolve('./controllers/authorize')),
+      careControllers = require(path.resolve('./controllers/cares')),
+      careValidators = require(path.resolve('./controllers/validators/cares'));
+
+const router = express.Router();
+
+router.route('/:id/cares')
+  .post(authorize.onlyLogged, careValidators.post, careControllers.post);
+
+router.route('/:id/cares/care')
+  .delete(authorize.onlyLogged, careValidators.del, careControllers.del);
+
+module.exports = router;
diff --git a/serializers/cares.js b/serializers/cares.js
new file mode 100644
index 0000000..8892fd2
--- /dev/null
+++ b/serializers/cares.js
@@ -0,0 +1,27 @@
+'use strict';
+
+const Serializer = require('jsonapi-serializer').Serializer;
+
+const voteSerializer = new Serializer('cares', {
+  id: 'id',
+  attributes: ['created', 'from', 'to'],
+  keyForAttribute: 'camelCase',
+  typeForAttribute(attribute, doc) {
+    if (attribute === 'from') return 'users';
+    if (attribute === 'to') return doc.type;
+  },
+  from: {
+    ref: 'username',
+    type: 'users'
+  },
+  to: {
+    ref: 'id',
+    type: 'ideas'
+  }
+});
+
+function care(data) {
+  return voteSerializer.serialize(data);
+}
+
+module.exports = { care };
diff --git a/serializers/index.js b/serializers/index.js
index dc8fdd8..3bc24ef 100644
--- a/serializers/index.js
+++ b/serializers/index.js
@@ -2,7 +2,8 @@
 
 const Deserializer = require('jsonapi-serializer').Deserializer;
 
-const comments = require('./comments'),
+const cares = require('./cares'),
+      comments = require('./comments'),
       contacts = require('./contacts'),
       ideas = require('./ideas'),
       ideaTags = require('./idea-tags'),
@@ -44,6 +45,6 @@ function deserialize(req, res, next) {
 }
 
 module.exports = {
-  serialize: Object.assign({ }, comments, contacts, ideas, ideaTags, messages, tags, users, votes),
+  serialize: Object.assign({ }, cares, comments, contacts, ideas, ideaTags, messages, tags, users, votes),
   deserialize
 };
diff --git a/serializers/votes.js b/serializers/votes.js
index 776350a..139dcf8 100644
--- a/serializers/votes.js
+++ b/serializers/votes.js
@@ -4,7 +4,7 @@ const Serializer = require('jsonapi-serializer').Serializer;
 
 const voteSerializer = new Serializer('votes', {
   id: 'id',
-  attributes: ['title', 'detail', 'created', 'value', 'from', 'to'],
+  attributes: ['created', 'value', 'from', 'to'],
   keyForAttribute: 'camelCase',
   typeForAttribute(attribute, doc) {
     if (attribute === 'from') return 'users';
diff --git a/test/cares.js b/test/cares.js
new file mode 100644
index 0000000..f8302e1
--- /dev/null
+++ b/test/cares.js
@@ -0,0 +1,202 @@
+'use strict';
+
+const path = require('path'),
+      should = require('should');
+
+const agentFactory = require('./agent'),
+      dbHandle = require('./handle-database'),
+      models = require(path.resolve('./models'));
+
+describe('Expressing interest in ideas (caring about ideas).', () => {
+  let agent,
+      dbData,
+      loggedUser;
+
+  afterEach(async () => {
+    await dbHandle.clear();
+  });
+
+  beforeEach(() => {
+    agent = agentFactory();
+  });
+
+  describe('Start caring about idea `POST /ideas/:id/cares`', () => {
+
+    let idea0,
+        requestBody;
+
+    beforeEach(async () => {
+      const data = {
+        users: 1, // how many users to make
+        verifiedUsers: [0], // which  users to make verified
+        ideas: [[{}, 0]]
+      };
+      // create data in database
+      dbData = await dbHandle.fill(data);
+
+      loggedUser = dbData.users[0];
+      idea0 = dbData.ideas[0];
+    });
+
+    beforeEach(() => {
+      requestBody = {
+        data: {
+          type: 'cares'
+        }
+      };
+    });
+
+    context('logged in', () => {
+
+      beforeEach(() => {
+        agent = agentFactory.logged(loggedUser);
+      });
+
+      context('valid request', () => {
+
+        it('Success 201', async () => {
+          const response = await agent.post(`/ideas/${idea0.id}/cares`)
+            .send(requestBody)
+            .expect(201);
+
+          // saved into database?
+          const dbCare = await models.care.read({ from: loggedUser.username, to: { type: 'ideas', id: idea0.id } });
+          should(dbCare).ok();
+
+          // correct response?
+          should(response.body).match({
+            data: {
+              type: 'cares',
+              relationships: {
+                from: { data: { type: 'users', id: loggedUser.username } },
+                to: { data: { type: 'ideas', id: idea0.id } }
+              }
+            }
+          });
+        });
+
+        it('Duplicate 409', async () => {
+          await agent.post(`/ideas/${idea0.id}/cares`)
+            .send(requestBody)
+            .expect(201);
+
+          await agent.post(`/ideas/${idea0.id}/cares`)
+            .send(requestBody)
+            .expect(409);
+        });
+
+        it('Nonexistent idea 404', async () => {
+          await agent.post('/ideas/11111111/cares')
+            .send(requestBody)
+            .expect(404);
+        });
+      });
+
+      context('invalid request', () => {
+        it('[invalid idea id] 400', async () => {
+          await agent.post('/ideas/invalid--id/cares')
+            .send(requestBody)
+            .expect(400);
+        });
+      });
+    });
+
+    context('not logged in', () => {
+      it('403', async () => {
+        await agent.post(`/ideas/${idea0.id}/cares`)
+          .send(requestBody)
+          .expect(403);
+      });
+    });
+  });
+
+  describe('Stop caring about idea `DELETE /ideas/:id/cares/care`', () => {
+
+    let idea0;
+
+    beforeEach(async () => {
+      const data = {
+        users: 2, // how many users to make
+        verifiedUsers: [0, 1], // which  users to make verified
+        ideas: [[{}, 0], [{}, 0]],
+        cares: [
+          [0, ['ideas', 0]],
+          [0, ['ideas', 1]],
+          [1, ['ideas', 0]]
+        ]
+      };
+      // create data in database
+      dbData = await dbHandle.fill(data);
+
+      loggedUser = dbData.users[0];
+      idea0 = dbData.ideas[0];
+    });
+
+    context('logged', () => {
+
+      beforeEach(() => {
+        agent = agentFactory.logged(loggedUser);
+      });
+
+      context('valid', () => {
+
+        it('[care exists] 204 and remove from database', async () => {
+
+          // first care should exist
+          const dbCareBefore = await models.care.read({ from: loggedUser.username, to: { type: 'ideas', id: idea0.id } });
+          should(dbCareBefore).ok();
+
+          await agent.delete(`/ideas/${idea0.id}/cares/care`)
+            .expect(204);
+
+          // then care shouldn't exist
+          const dbCareAfter = await models.care.read({ from: loggedUser.username, to: { type: 'ideas', id: idea0.id } });
+          should(dbCareAfter).not.ok();
+        });
+
+        it('[care doesn\'t exist] 404', async () => {
+          await agent.delete(`/ideas/${idea0.id}/cares/care`)
+            .expect(204);
+
+          await agent.delete(`/ideas/${idea0.id}/cares/care`)
+            .expect(404);
+        });
+
+        it('[idea doesn\'t exist] 404', async () => {
+          await agent.delete('/ideas/0000000/cares/care')
+            .expect(404);
+        });
+      });
+
+      context('invalid', () => {
+        it('[invalid idea id] 400', async () => {
+          await agent.delete('/ideas/invalid/cares/care')
+            .expect(400);
+        });
+      });
+    });
+
+    context('not logged', () => {
+      it('403', async () => {
+        await agent.delete(`/ideas/${idea0.id}/cares/care`)
+          .expect(403);
+      });
+    });
+  });
+
+  describe('See who cares about the idea `GET /ideas/:id/cares`', () => {
+    it('todo');
+  });
+
+  describe('Include info whether I care about the idea when reading it', () => {
+    it('todo');
+  });
+
+  describe('See ideas cared for by given user(s) `GET /ideas/:id?filter[caring]=username1,username2`', () => {
+    it('todo');
+  });
+
+  describe('How many users care about the idea?', () => {
+    it('todo');
+  });
+});
diff --git a/test/handle-database.js b/test/handle-database.js
index b0fb873..c99a378 100644
--- a/test/handle-database.js
+++ b/test/handle-database.js
@@ -25,7 +25,8 @@ exports.fill = async function (data) {
     ideaTags: [],
     ideaComments: [],
     reactions: [],
-    votes: []
+    votes: [],
+    cares: []
   };
 
   data = _.defaults(data, def);
@@ -138,6 +139,16 @@ exports.fill = async function (data) {
     vote.id = newVote.id;
   }
 
+  for (const care of processed.cares) {
+    const from = care.from.username;
+    const to = { type: care._to.type, id: care.to.id };
+
+    const newCare = await models.care.create({ from, to });
+
+    // save the care's id
+    care.id = newCare.id;
+  }
+
   return processed;
 };
 
@@ -338,5 +349,15 @@ function processData(data) {
     };
   });
 
+  output.cares = data.cares.map(([from, to]) => {
+    const [type, id] = to;
+    return {
+      _from: from,
+      _to: { type, id },
+      get from() { return output.users[this._from]; },
+      get to() { return output[this._to.type][this._to.id]; }
+    };
+  });
+
   return output;
 }