Apple's agreement with AT&T prohibits VoIP apps, so Skype was forced to develop a client that works on WiFi only.
AT&T warned Apple that SlingPlayer Mobile would violate its terms of service, so the program was neutered to run on WiFi only. Of course, AT&T sells millions of Windows Mobile and S60 phones that run it on 3G just fine, but they have no way of controlling them like the App Store.
Apple decided that the only reason you'd want to use Bittorrent was to infringe copyrights, so it rejected Drivetrain, an app that didn't actually torrent anything -- it just controlled the Transmission client running on your computer.
Tweetie is one of the most popular Twitter clients out there, but that didn't stop Apple from rejecting the 1.3 update when a dirty word was trending on Twitter -- content that Tweetie doesn't even control.
It's still not totally clear what happened, but Apple's opaque App Store approval process resulted in the Ninjawords dictionary being both censored and rated 17+ -- overkill by any means.
Okay, so we understand why Apple deleted the Baby Shaker app -- but why was it approved in the first place?
Apple's policy towards obscene and pornographic content is pretty vague at the moment, but apps like Hottest Girls clearly crossed the line. The only problem is that the line appears to be constantly moving.
It's not at all clear why all emulators are banned from the App Store, but that means an entire world of NES, SNES, and C64 games are locked away -- although word is Apple's reconsidering.
Google Voice is the big one -- the one that caught the FCC's attention. Apple says it'll duplicate iPhone functionality and confuse users, but we say the people should be free. Let's hope the good guys win.