A week ago, Microsoft announced that "all multiplayer gaming will be completely free on Games for Windows LIVE, including cross-platform gameplay with XBOX 360 users"; but today they are singing a (slightly) different song.
"Last week we announced that we were taking off the Gold-only restriction for multiplayer gaming over Games for Windows- Live", wrote a Microsoft spokesperson. "For a limited time, we are offering free online multiplayer on Xbox 360/Games for Windows titles that offer Live cross platform play."
"This promotion won't last, so we encourage everyone to take advantage of it while they can."
For the record, Microsoft's Major Nelson was wrote last week that "Games for Windows - LIVE - our online multiplayer gaming service for Windows, now offers completely free multiplayer. No exceptions - multiplayer is completely free, even cross-platform gameplay with XBOX 360 users."