"A way to create tiny discussions" was an idea I had for a start-up 3 years ago that I simply never got around to doing. I think there is a massive potential for such a thing, given that there currently isn't any easy way (that I know of) to create a tiny little forum somewhere quickly and easily. Right now, the closest thing is creating a post, or a note, or a group on Facebook and having really crappy discussions ensue. The Facebook discussion system is just awful, and it's a walled garden.
I think you should go with the "tiny discussions" idea, since I regrettably haven't.
There's no maybe about a tour/features/walkthrough... you need it. You need to adequately describe what your service does and why I should use it.
Like I said before, I've been thinking about the commenting space for about 3 years now. I've watched things like Disqus, Facebook Pages, and Ning pop up well beyond the time I had the idea of simplifying and unifying discussion. And, still, it seems nobody has managed to nail down the massive market of tiny forums.
To put this in perspective, google for virtually any type of forum. iPod forum. Nissan forum. Twilight Forum. Etc. The top results you'll get for each of this will be massively popular and lucrative message boards. Basically, they'll be a good domain name with PHPBB loaded up in them, and that's sufficient to get a critical mass of people using it. Now, think to yourself: in the next x years, what new products, movies, brands, etc will be created that will have potential for these similar types of lucrative forums? You can't know the answer. But as the future unfolds, the market will know. And if you could capture some of this market, you'd be in for a lot of traffic.
My conclusion is that the best way to go about this is to have users create the forums. I think there is a lot of money to be made in discussion forums, and user-generated forums is how you guarantee you are the first to capture the market's need for a particular forum. Think: A wikipedia of forums.
I realize this post might be pretty incoherent and barely related to your weekend project. Sorry, I haven't eaten breakfast yet.