diff --git a/plone/app/discussion/comment.py b/plone/app/discussion/comment.py
index b897730..97bfa3f 100644
--- a/plone/app/discussion/comment.py
+++ b/plone/app/discussion/comment.py
@@ -1,6 +1,6 @@
 """The default comment class and factory.
 """
-
+from datetime import datetime
 from zope.interface import implements
 from zope.component.factory import Factory
 
@@ -26,6 +26,7 @@ class Comment(Explicit, Traversable, RoleManager, Owned):
     __parent__ = None
     
     comment_id = None # int
+    reply_to = None # int
 
     title = u""
     
@@ -44,14 +45,15 @@ class Comment(Explicit, Traversable, RoleManager, Owned):
     def __init__(self, id=0, conversation=None, **kw):
         self.comment_id = id
         self.__parent__ = conversation
+        self.creation_date = self.modification_date = datetime.now()
         
-        for k, v in kw:
+        for k, v in kw.items():
             setattr(self, k, v)
 
     @property
     def in_reply_to(self):
         # TODO
-        return None
+        return self.reply_to
     
     @property
     def __name__(self):
diff --git a/plone/app/discussion/conversation.py b/plone/app/discussion/conversation.py
index 7e4a0a7..cfd35fe 100644
--- a/plone/app/discussion/conversation.py
+++ b/plone/app/discussion/conversation.py
@@ -60,26 +60,41 @@ class Conversation(Persistent, Explicit):
     @property
     def total_comments(self):
         # TODO
-        return 0
+        return len(self._comments)
     
     @property
     def last_comment_date(self):
         # TODO
-        return None
+        return self._last_comment_date
     
     @property
     def commentators(self):
         # TODO:
         return set()
     
-    def getComments(start=0, size=None):
-        # TODO
-        pass
+    def getComments(self, start=0, size=None):
+        return self._comments.values()
     
-    def getThreads(start=0, size=None, root=None, depth=None):
-        # TODO
-        pass
+    def getThreads(self, start=0, size=None, root=None, depth=None):
+        return self._comments.values()
     
+    def addComment(self, comment):
+        id = len(self._comments) + 1
+        self._comments[id] = comment
+        comment.comment_id = id
+        
+        commentator = comment.creator
+        if not commentator in self._commentators:
+            self._commentators[commentator] = 0
+        self._commentators[commentator] += 1
+        
+        self._last_comment_date = comment.creation_date
+        
+        reply_to = comment.in_reply_to
+        if not reply_to in self._children:
+            self._children[reply_to] = IISet()
+        self._children[reply_to].insert(id)
+        
     # Dict API
     
     # TODO: Update internal data structures when items added or removed
diff --git a/plone/app/discussion/interfaces.py b/plone/app/discussion/interfaces.py
index 315adf7..db2c8cc 100644
--- a/plone/app/discussion/interfaces.py
+++ b/plone/app/discussion/interfaces.py
@@ -73,6 +73,11 @@ class IConversation(IIterableMapping, IWriteMapping):
         in order to give enough context to show the full  lineage of the
         starting comment.
         """
+        
+    def addComment(comment):
+        """Adds a new comment to the list of comments, amd returns the 
+        comment id that was assigned.
+        """
 
 class IReplies(IIterableMapping, IWriteMapping):
     """A set of related comments in reply to a given content object or
diff --git a/plone/app/discussion/tests/test_api.py b/plone/app/discussion/tests/test_api.py
index 300354e..2e28195 100644
--- a/plone/app/discussion/tests/test_api.py
+++ b/plone/app/discussion/tests/test_api.py
@@ -1,5 +1,5 @@
 import unittest
-
+from datetime import datetime, timedelta
 from base import TestCase
 
 from zope.testing import doctestunit
@@ -13,7 +13,10 @@ from Products.Five import fiveconfigure
 from Products.PloneTestCase import PloneTestCase as ptc
 from Products.PloneTestCase.layer import PloneSite
 
-class APITest(TestCase):
+from plone.app.discussion.conversation import Conversation
+from plone.app.discussion.comment import Comment
+
+class ConversationTest(TestCase):
     def afterSetUp(self):
         # XXX If we make this a layer, it only get run once...
         # First we need to create some content.
@@ -21,13 +24,29 @@ class APITest(TestCase):
         typetool = self.portal.portal_types
         typetool.constructContent('Document', self.portal, 'doc1')
             
-    def test_test(self):
-        raise NotImplementedError
+    def test_add_comment(self):
+        # Create a conversation. In this case we doesn't assign it to an
+        # object, as we just want to check the Conversation object API.
+        conversation = Conversation()
+        
+        # Add a comment. reply_to=0 means it's not a reply
+        comment = Comment(conversation=conversation, reply_to=0)
+        comment.title = 'Comment 1'
+        comment.text = 'Comment text'
+        
+        conversation.addComment(comment)
+        
+        # Check that the conversation methods return the correct data
+        self.assertEquals(comment.id, '1')
+        self.assertEquals(len(conversation.getComments()), 1)
+        self.assertEquals(len(conversation.getThreads()), 1)
+        self.assertEquals(conversation.total_comments, 1)
+        self.assert_(conversation.last_comment_date - datetime.now() < timedelta(seconds=1))
     
 
 def test_suite():
     return unittest.TestSuite([
-        unittest.makeSuite(APITest),
+        unittest.makeSuite(ConversationTest),
         ])
 
 if __name__ == '__main__':