2) Why would someone use this? Right off the bat I don't get why I should use this instead of email. In order to start a discussion I need to know the email addresses of the initial participants whereas newsgroup or mailing list posts go out to hundreds or thousands of people I may or may not know ahead of time. If I need to know exactly who's going to be involved from the start it's easier to use my mail client.
I understand that the discussion can be made public on here, but what's the point? Sure, you don't need a newsgroup already set up, but a newsgroup is also a good starting point for someone looking for discussions about a particular topic. I just don't understand what need this is fulfilling. This needs to be made clear on the front page so potential users don't navigate away 15 seconds after landing on it with the impression that this is a reinvention of the wheel.
[edit] There's a small grammatical error on the About page. "Discuss any topic with lot's of people right now and waste no time for registration." should be "Discuss any topic with lots of people right now and waste no time for registration." "Lots" is plural; "lot's" is possessive.