Why are rars used on P2P networks?
Quite often those split rar files originate from usenet. A number of usenet servers and even download websites generate download links which are functional just a short time – so in order to help users that have slow connections to download the whole content they split them up into smaller parts. When downloading a file of large size (600mb or more) there is the risk of the Avi corrupting, which led to his practice of using Rar.