This aims to be a list of actual AppStore rejection criteria based on our, and hopefully your, direct experience. Please add to this compendium by leaving your own rejection reasons in the comments and we’ll add them to the main list on a daily basis.
1) Vibration. It is not permitted to use continuous vibration in your apps - short bursts as warnings is all that is allowed. Don’t bother trying to set up a timer to keep the vibration going, it will cause your app to be rejected.
2) Linking to private frameworks. This is obvious, but somehow in playing around with stuff we had linked to the MoviePlayer.framework. That’s a no-no, and cost us about ten days while we unlinked that framework, recompiled, and then resubmitted.
3) Improper handling of editing in tableview cells. Also obvious, but be aware that if you enable table cell editing, you’ll have to manually specify which cells should respond to editing controls and which should not. We had some random prefs cells in one of our early apps that were able to be swiped to bring up a ‘delete’ badge. Of course it didn’t do anything, but Apple justly considered this poor design and rejected our app.
4) Icons. Make sure the 57 pixel icon is identical to the 512 pixel version. Also, use a different icon if you are creating ‘lite’ and ‘pro’ versions of your app (i.e., free and paid). Using the same icon for both sends your app straight to … you guessed it … teh bin.
5) Flatulence. Don’t even try. ’nuff said.
6) Copying existing functionality. This one is much more subtle and insidious, and has probably affected the great percentage of developers. In addition to the widely publicized Podcaster debacle, reports from user comments indicate that Apple is casting a wide net when looking for duplicated functionality. Mini web browsers, or apps that essentially show web pages, seem particularly vulnerable, even if they add new and/or useful functionality. Stay away from email clients as well.
7) Using appropriate keyboard type. If your app asks for a phone number or other numeral-only input and you present a keyboard that also includes the possibility of entering standard alpha-numeric input … yep. (Thanks Jeremy1026)
Version numbers. If your app is currently at version 0.99 or below, you’d better consider giving it a promotion as Apple seems to prefer 1.0 and above. One of ours was recently rejected for being .016, with a message suggesting that our version number wasn’t even numeric. When we resubmitted the same app from scratch as version 1.0, it went through.
PS: for those who haven’t seen this yet 
How Apple Decides whether or not to put an app on the App Store
September 23rd, 2008 at 5:05 am
I believe any use of fart sounds will get you rejected. Both “Pull My Finger” and a “Whoopie Cushion” app were rejected, apparently because of this.
September 23rd, 2008 at 5:35 am
Try and get a app approved for an overlapping service like mail. The app will be rejected.
Furthermore, this is a good initiative. Keep up the good work over there.
September 23rd, 2008 at 6:11 am
[...] updated list and new entries can be found here. Discuss this topic in the [...]
September 23rd, 2008 at 9:13 am
5) Apps can not duplicate functionality of Apple’s pre-installed apps. Ex. I made a simple app that loads the 4 Woot pages into UIWebViews with a UITabBar to make checking each site done in a max of 5 taps. Apple said that the app was simply remapping book mark buttons of Safari therefore duplicating functionality, and therefore, rejected.
September 23rd, 2008 at 8:59 pm
But what about Instapaper? That overlaps Safari in that you can view webpages on it. THe difference is you can view them offline, perhaps, but it’s still difficult to see why this doesn’t overlap while something that focuses on gmail accounts does [forgot the apps' name] I wonder if it would have got accepted if submitted now?
September 23rd, 2008 at 11:16 pm
Having the word “Demo” on one of the screens, as in demonstration of what’s possible (the app was not a limited ‘lite’ version) caused our app to be rejected a few months ago. Removing the word got it accepted eventually.
October 21st, 2008 at 1:45 am
[...] Program, which costs either $99 or $299. And still then, your application can get rejected, for a variety of reasons, including the aforementioned [...]
December 30th, 2008 at 10:49 pm
[...] in fart apps recently, it was only a matter of time… Flatulence was criteria 5 on the Unofficial App Store Rejection Criteria list. With farting given the all-clear, I figured more of those criteria would start to open [...]