I’ve loved this idea for a while, just saw it in action. Sometimes promotion is much more valuable to a startup or project than cash. In this case the site is charging the user by either $2 or to post to twitter about it.
Love it, well done and thank you for doing that. Would like to see this be more commonplace. I’ve also seen balsamiq doing this (review coming!).
More and more products are coming onto the marketplace, and the killer is lack of community over lack of money. You can raise more money, but the community will keep moving past you.