µTorrent, or uTorrent (see ) is a proprietary adware BitTorrent client owned and developed by BitTorrent, Inc. With over 100 million users it is the most widely used BitTorrent client outside China; globally only behind Xunlei. The "µ" (Greek letter "mu") in its name comes from the SI prefix "micro-", referring to the program's small memory footprint: the program was designed to use minimal computer resources while offering functionality comparable to larger BitTorrent clients such as Vuze or BitComet. The program has received consistently good reviews for its feature set, performance, stability, and support for older hardware and versions of Windows.