One of the features I like best about Twitter is that everything is public, except if you decide to make your tweets private. Apparently there is a business model for having your own private Twitter amongst family and friends. That is the idea behind Micromobs.
On Micromobs, you can create “mobs” which has stream messages that are relevant for each user. Micromob users can also push messages to Twitter and Facebook. Groups can also be made private. Micromobs started at the Founders Institute incubator. The founder of Micromobs is Ajay Kamat. [TechCrunch]