There have been quite a few news stories on Microsoft's XBOX Live service doing fairly well.
Microsoft has more than 750,000 customers paying an average of $50 a year to access Xbox Live and logging approximately 500,000 hours of online game play each day. Not too shabby to think of 500,000 VoIP hours or 30,000,000 VoIP minutes per day!
I should mention that I have an Xbox connected to my 65" Mitsubishi TV set with full Dolby/DTS 7.1 surround sound and a subwoofer that makes the walls shake when I blow something up in a game... yet I have not joined Xbox Live.
I've been tempted to sign up, but I fear getting addicted and having my wife leave me. : )
In any event, here's an interesting news story about Microsoft using XBOX Live to "introduce" VoIP to the masses: