Mostly because they changed it so that the users cannot respond to other users' posts. Only the asker and individual answerer can add comments on any answer.
That seems confusing, so I'll clarify by saying that on Askville, no one but me, the asker of the question, would be able to respond to your post. It killed the 'community' feeling for me. I enjoy the banter and the anticipation of certain other members participating on certain questions. I had grown to know the feminists, the grouchy old men, the liberals and conservatives, the foodies, etc. Grown to appreciate other members despite fundamental differences in certain areas.
They took away the give and take.