Good point. AppStoreHQ's 'Hottest' list is built on streaming blog post discovery, and the stream is what's on the home page (kind of like Hype Machine does for music) - so any app that gets a mention from any of 70+ "canonical" blogs, or any blog that drops an AppStoreHQ review widget into its review - will show up in the stream.

So yeah, you have to at least have gotten some traction somewhere to get into the stream, but the bar is pretty low. (That said, about half the apps in the App Store have never even received a user rating - they're still in AppStoreHQ's search results, but they'll need a little love to get out of the basement).