BitTorrent PRO is a program for downloading and creating torrent files. This application has an intuitive user interface, very low CPU and memory usage, a chatting function, and the ability to preview files while downloading. It also has features found in torrent programs, such as the ability to set upload and download limits, distributed Hash Table, and support for proxies.
Its advantage over plain HTTP is that when multiple downloads of the same file happen concurrently, the downloaders upload to each other, making it possible for the file source to support huge numbers of downloaders with only a modest increase in its load.
Serving large files creates problems of scaling, flash crowds, and reliability. The key to cheap file distribution is to tap the unutilized upload capacity of your customers.