Microsoft have announced that they’ll be shutting down their PC marketplace Games for Windows Live according to a post on their Xbox Support page. The reason for the closure is due to the retirement of Microsoft Points in exchange for local currencies so if you have any Microsoft Points left on your account, you better spend up!
The FAQ page on Xbox.com reads:
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. 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
The Games for Windows Live client won’t be going anywhere however, just the ability to purchase software through the service. Previously purchased games and content will still be available for customers.
[Source: Xbox Support]