In Response to User Demand, Pidgin Forks
Pidgin, the multi-platform open-source IM client that used to be called Gaim, has a lot of fans. The recent version 2.4.0 removed the user's ability to manually resize the input box, and many of those fans got mad.
Version 2.4.1 made some improvements, but meanwhile the project has forked. A set of developers have created Funpidgin is a version of Pidgin with a manually resizable input box and four other additional features so far.
According to the Funpidgin site, "What makes us different from the official client, is that we work for you. Unlike the Pidgin developers, we believe the user should have the final say in what goes into the program."
That's what's nice about open source: everyone can work together, or you can split off and do your own thing.