If you have iOS 5 installed in your terminal, then it is very likely that at least once you will see that instead of the name of an application, the writing Cleaning… and the application icon becomes deleted. If you didn't know yet, that application was doing a simple cleaning of some files saved in it at those times. Basically, then the cache and temporary files from the application were deleted and everything is part of a new system implemented by Apple in iOS 5 for iDevices. The system allows developers to create applications that "clean" themselves and in case of an update through iTunes, the backup will not contain those temporary files from the applications.
Apple designed this system to reduce the time needed to make a backup, especially since now we have the option to do it even via Wi-Fi. In conclusion, if you see the writing Cleaning… next to an application, you know that it also deletes some files that are not important anyway.
