Pidgin on MacOSX is described as 'This is an unofficial native port of Pidgin to Mac OS X. It uses native GTK+ (www.gtk-osx.org) which provides better integration and does not require X11. It also comes with more plugins out of the box, including OTR' and is a instant messenger in the social & communications category. There are more than 25 alternatives to Pidgin on MacOSX for a variety of platforms, including Windows, Linux, Mac, BSD and iPhone. The best alternative is Jitsi, which is both free and Open Source. Other great apps like Pidgin on MacOSX are Pidgin, Trillian, Imo and Empathy.