Big-O Software used to make AIM+
Big-O Software was the home of AIM+, a nice (and free) add-on for AIM (AOL Instant Messenger) that features ad-blocking, multiple logins, nicknames, and more.
[update: Download AIM+ 2.2.1 from download.com. According to wikipedia, AIM+ is not compatible with AIM version 5.0 or greater. cf. AIM+ Found to Contain a SpyWare, AIM+ creators delete “spyware” feature]