The WinMerge 2011 series is a fork of the original WinMerge application published on SourceForge by Thingamahoochie Software. It was an escape from the complex situation that existed with respect to WinMerge 2.x at that time. ATL/MFC dependencies have been removed to support building with Visual C++ Express editions. Thanks to the advent of Visual Studio Community, the move away from ATL/MFC lost some of its point, although I think it does at least represent sort of a cleanup which the codebase sort of demanded for. Anyhow, winmerge.org finally recovered from said complex situation by making Takashi's fork official, and that is extraordinarily cool.