Microsoft Closing Games for Windows Live Marketplace

Microsoft Points are going away in the next Xbox 360 update, which will have a huge effect on PC gamers using GFWL.

The Games for Windows Live Marketplace is closing this month. Microsoft has detailed the rhyme and reason as well as what this means for PC players:
"As part of the recent Xbox 360 system update, Microsoft Points will be retired and the Xbox.com PC Marketplace will be closed as of August 22, 2013," Microsoft explains. "We encourage you to spend your Microsoft Points balance prior to this change. Although you will not be able to purchase new games, you can continue to enjoy previously purchased content by downloading it through the Games for Windows Live client software as usual."
When Xbox 360's system update happens, Microsoft Points will convert to an equivalent cash value on your Live account -- because the Marketplace is going away on PC, and there will be nothing to buy on GFWL, there will be no rollover. As Microsoft mentions, you should spend your Microsoft Points before August 22 to avoid losing those funds altogether.

To be clear, Games for Windows Live as a service will continue to operate. A series of frequently asked questions on Xbox.com details the consequences. Your existing purchased content remains yours, although the ability to buy it through the Marketplace will vanish.
This is another major change in the evolution of Microsoft Live, which will see major overhauls in the coming weeks leading up to Xbox One's launch.