Apple has pulled an app named Clueful from the App Store, though it hasn't been completely forthcoming yet as to why the app was pulled. Clueful is an app from a company called Bitdefender that's designed to let iPhone users monitor what their other apps are doing or sharing in terms of usage. One of Bitdefender's reps does say that "most app developers use [Clueful's] information for legitimate purposes, others might not," so it's possible that the app allowed for some less-than-secure activity on the part of app developers or users. It's unclear what that is, however. It seems from the project's FAQ that Clueful did try to interact with other apps on the iPhone, and that seems like something open to exploits and issues.
At any rate, the app's gone now. If you already have it installed, you can obviously keep it, but for now, there won't be any new installs from the App Store.
The big question here is, of course, why the app was approved in the first place. Bitdefender didn't add any functionality to the app to get it removed, so there must have been something Apple missed. Hopefully, we'll hear more in the future about the problems behind Clueful, and we'll get a good reason why Apple suddenly changed its mind.