It's the version that was published with AOL's TiK client version 0.75, which appears to be the last one ever published. There are a few other Unix programs that use it, I think. I really couldn't tell you though. AOL used to keep a list of them, but no more. The Client 1.
G stands for all sorts of good things.
Girls, Godzilla, GTK, graham crackers, whatever. When adding a new buddy, you just type in a new group name. Future versions intend to handle this and renaming groups better. It is coming. AOL's legal staff told us no-no. 5.