In August of 2010, tap tap tap's Camera+ got pulled from the App Store because it implemented a feature which violated Apple's Developer Agreement at the time. VolumeSnap allowed Camera+ users to use the "+" volume button on the iPhone as a physical shutter switch for taking photos with the iPhone. After a four-month hiatus, Camera+ came back to the App Store with a redesigned and improved interface, but VolumeSnap was nowhere to be found.
Things certainly changed over the next few months; Apple "Sherlocked" the VolumeSnap feature for iOS 5's own Camera app. It worked exactly the same way as it did in Camera+, and I imagine tap tap tap must have been a bit peeved at Apple for a while.
Camera+ has now been updated with the VolumeSnap feature returned in all its glory, and as you can tell from the release notes, tap tap tap is pretty excited about it. The feature works just like Apple's, um, borrowed implementation: press the "+" volume button to take a picture while you're in the app and lining up a shot, and snap, there's your picture. You can still use the touchscreen shutter button instead if you prefer, and tap tap tap also has instructions for disabling VolumeSnap if you decide you dislike it (though I can't imagine why anyone would).
VolumeSnap makes an already great photography app even more useful. Though the whole saga hasn't exactly made Apple look like the good guy, at least it eventually came to its senses and allowed this great feature through.