Twitter is primarily a broadcast tool. It’s not very easy to follow a discussion unless you happen to be following both of the people involved in the conversation – in fact, it’s impossible to follow it in conversational type format.
Facebook allows comments, likes, dislikes, media, etc… to be added in response to updates. So in this way, Facebook actually facilitates an efficient dialogue amongst groups of people or even 2 individuals.
That’s it – there’s the main difference between Twitter and Facebook.
And in my opinion, Twitter better figure out a way to engage conversation within Tweets are they are going to be outgunned, and taken down, by Facebook!
People enjoy the conversation piece that Facebook offers, and with Twitter, it’s more like spam messaging than it is dialogue.