Unique website ideas?

[Matt]

I like #2 of Zack's personally, everyones trying to do their own Twitter clone. What they don't realize is that, Twitter was formed out of a unique idea, and if you try to copy that, you're not unique at all.

I too have an idea up my sleeve, however am not revealing it until I can work on it. Mind you, Website Inquirer was formed off a pretty unique idea...

It completely depends on what you want to do, I guess. Start a forum that's truly unique, the threads are based off in trends and the forums expand to a user's own preference... A bit all over the place, but it could work.