According to joystiq.com, rumor has it that Microsoft is about to add the built-in Windows 7 games Solitaire, Minesweeper, Spider Solitaire, Freecell, etc. to their service “Games for Windows LIVE”.
If you wondered where the Games are in Windows 7, Microsoft disabled them by default:
Enable Games in Windows 7
You already get the Windows game “Tinker” as a reward for joining Games for Windows, so it would make a lot of sense to start using the other Windows Games for marketing purposes. Tinker, one of the few hidden surprises of Vista Ultimate, was one of the best Windows games ever. Hopefully, they will also add this game to Windows 7, because a leaderboard for Tinker would be really, really awesome.
Wait, a leaderboard? Yep, the unspecified source also says that there will be achievements, a chat and a leaderboard!
Achievement unlocked: Failed at Minesweeper for the #30004589 time on your first try.