A lot of people use Twitter to have conversations with others, but that's not really what it was built for. Initially, Twitter was just supposed to be a place to update what you are doing; the @reply only came around because people started using it to direct a conversation at another user. Now conversations are one of the most interesting things about Twitter, and a new startup launching in private beta today at TechCrunch50 , Lissn , wants to build a new platform from the ground up with conversations in mind. If you've seen the video demos or had a chance to use Google Wave at all, Lissn may seem familiar — it has the same type of real-time conversation aspect. The difference, of course, is that this is the main function of Lissn, while Wave is trying to be a lot of different things wrapped into one. Lissn is all about having conversations with people, and allows others to watch, and join in as they'd like. TechCrunch50 Conference 2009 : September 14-15, 2009, San Francisco