Microsoft has offered TechNet subscriptions since 1998 as a massive packet of CDs, and evolving into a download option as broadband connections became common. For an annual subscription fee of a few hundred dollars, subscribers get the right to download nearly every desktop and server software Microsoft sold with multiple product keys.
While the software was licensed for evaluation purposes only, but that restriction is part of the license agreement and not enforced in the software itself. It was a way to get cut-rate Windows client and server upgrades and licenses with product keys would up activating Windows on PCs deployed.
What appears to have killed the programme off was that the deal was great for software pirates, who figured out long ago that they could subscribe to TechNet and sell the keys. Microsoft cut the number of product keys available to TechNet subscribers in 2010 and again a year ago, in 2012. It also changed the terms so that usage rights expired when the subscription did.