eMule is a free peer-to-peer file sharing application for Microsoft Windows. Started in May 2002 as an alternative to eDonkey2000, eMule now connects to both the eDonkey network and the Kad network. The distinguishing features of eMule are the direct exchange of sources between client nodes, fast recovery of corrupted downloads, and the use of a credit system to reward frequent uploaders. Furthermore, eMule transmits data in zlib-compressed form to save bandwidth.
eMule is coded in C++ using the Microsoft Foundation Classes. Since July 2002 eMule has been free software, released under the GNU General Public License; its popularity has led to eMule's codebase being used as the basis of cross-platform clients aMule, JMule, xMule, along with the release of many eMule mods (modifications of the original eMule) on the Internet.
As of March 2012, it is the most popular download on SourceForge, with over 639 million downloads.
Read more about EMule: History, Basic Concepts, EMule Mods, Fake EMule Sites and Malware, Chinese Mods of EMule Client