I want to see a screenshot on the front page. Show me what I'm getting for my money. I clicked around a few links - nothing.
How is this different to GetSatisfaction, GitHub Issues, or even a shared GoogleDoc?
No https - so I'm not typing in a password. Why can't I register with GitHub, Twitter, Facebook logins etc?
Your sign up form doesn't tell me what the validation criteria are. How am I meant to know that the password has to be 6 characters or more?
I'm not saying it's a bad idea - but your landing page doesn't convince me to sign up. Show people what you're selling and make it easy for them to trust you.