Microsoft has officially discontinued the sale of Windows 7 and Windows 8. As of October 31, 2014, some versions of Windows 7 and 8 will no longer able available for consumer purchase.
Although this move might seem abrupt, it actually has been planned for quite some time according to Microsoft's Windows lifecycle fact sheet that was last updated in April 2014. This fact sheet has a list of previous and current operating systems and states when the Microsoft will discontinue support and sales of a product.
As of October 31st, Windows 7 Home Basic, Home Premium, and Ultimate will no longer be available for purchase, directly from a retailer. Also the aforementioned OS's will not be pre-installed on any computers that are being sold through OEM's. Windows 7 Professional and 8 will also no longer be available for retail purchase, but these OS's will still be able to be found on PC's being sold by OEM's.
This move should definitely start tipping the scales when it comes to Windows 8 and 8.1 adoption. Last we checked, Windows 7 was still dominating with 52.71% of the market share. With a 2015 release set for Windows 10, it'll be interesting to see how much market share Windows 8 / 8.1 will be able to gain in such a short amount of time.