Microsoft's finally pulling the plug on Games for Windows Live (GfWL) as of next year, but customers are already feeling the repercussions. As of August 25th, the GfWL Marketplace was shut down rendering downloadable content for all games purchased through the marketplace (and some that weren't) unavailable. The plus side is that you'll still be able to download your DLC if you've already purchased it; if you haven't, well, you're out of luck.
I first noticed this when I went to check on Microsoft Flight through Steam, noticing that only the game play trailers were available. Puzzled, I checked the Steam forums only to discover that Microsoft essentially took their ball and went home. Not only did they pull the plug on Flight through the marketplace, but they also pulled it from Steam!
For most of you, this probably won't matter. It simply means that any GfWL-enabled games will be reduced to single player functionality by next year. Age of Empires, Flight, and numerous other titles that had multiplayer capabilities will be affected. If you were just getting into a new game or planning to purchase one that's published by Microsoft, you're screwed. If you're playing a game that requires GfWL functionality (such as for saving progress), you'll be able to play it unimpeded until next year. After 2014, games requiring GfWL for save game functionality may be rendered unplayable. Others, like Fuel, have 3rd party patches that provide some modicum of local storage for user progress, but that may not be possible for most other games.
The hilarious (but nevertheless disappointing) side is the response from a number of pro-Microsoft gaming pundits. Apparently so many of them have Microsoft's dick stuffed so far down their proverbial throats that, through their bleary, watery eyes, they can't see anything but joy. To many of them, screwing over PC gamers is a good thing.