TipDrop is clever idea -- a micro-blogging platform that's topic-based rather than member-based (like Twitter). Instead of "following" a particular person, the user posts to (or reads, or creates) "tip sheets" organized by topic.
Its creator seems to envision it as a narrow-topic ("how to get more hits to your blog," etc.) kind of thing, but I've already created a more general "tip sheet" for breaking political news, which I assume is allowable and which could constitute a continuous reciprocal "tip timeline" for political bloggers.
TipDrop appears to have launched in beta about a minute before I got an email about it (the beta announcement is dated July 17th). I can see it doing big things, if they issue an API and people are willing to create third party apps to make good use of it.
Anyway, I'm in.