Could be worse. I still remember when Microsoft maintained both "Windows Messenger" and "MSN Messenger" as separate apps with separate update schedules and version numbers even though it was the same product. That was confusing.
As best i recall it started with Windows Messenger, aimed at intranet use (and with a client bundled with Windows, natch). Then MS used the same protocol to offer a AIM competitor. In the end though what they killed seemed to be IRC...
