Game Center should allow non-game iOS apps to register for achievements and leaderboards. Think about it: Largest Dropbox File, Most TextExpander Time Saved, Longest iStat Uptime, Most LoseIt Pounds Lost This Week.
David Chartier nails a great idea. I’d love to make Game Center-shareable achievements in Instapaper, but I don’t think there’s any chance that Apple would approve it, even after today’s improvements. (via marco)