At Cynapse, we recently released the latest version of cyn.in 2.1 (last week) and the response has been nothing short of amazing!
One of the (among many) cool things that we did in cyn.in was to put in microblogging collaboration. What’s that you ask? 
Here’s the quote from Wikipedia:
Micro-blogging is a form of multimedia blogging that allows users to send brief text updates (say, 140 characters or fewer) or micromedia such as photos or audio clips and publish them, either to be viewed by anyone or by a restricted group which can be chosen by the user. These messages can be submitted by a variety of means, including text messaging, instant messaging, email, MP3 or the web.
What’s different in cyn.in, of course, is that you can actually discuss each individual “Status message” (what we call each microblog post instance). I think that this is one of the key problems plaguing the world of microblogging as we know it.
While various ways have developed to solve this problem (You can @dhiraj on twitter, for example), there’s not many systems that support commenting like we do – off hand, I do not know of a single one. In cyn.in each status mesasge is a full-blown cyn.in item. Not being a second cousin to the rest of the applications means that you can actually go ahead and have fully threaded discussions on Status messages, among the many other things (like having them show up in Smart Views, for example).
If you use the cyn.in desktop (made in Adobe AIR) as much as I do, then you quickly realize that discussions are the norm, and not the surprising thing that it sounds. Yes, cyn.in desktop lets you type in a reply, or add a new message to a discussion so quickly that it leaves you amazed with that distinct feeling: “That’s all? There must be something else I have to do to get my message across.” Well no, there isn’t. It’s already popped on everyone’s desktop.
Take my word. Or have a look at the cyn.in screenshots. Either way, you should buy it – now that it has a reduced starting price of just $99/mo. You’ll be happier. Your day will be filled with bright sunshine, and you will go around smiling at everything / everyone.
Or am I just overpitching?
You tell me. I never know.