More details on the freeness of Windows 10:

http://arstechnica.com/information-t...stions-remain/

From the tone of the article, I get the impression that it's yours to keep if you update within the first year (a bit like the Windows 8 Pro upgrade for $40). Some strings attached, but nothing that will matter to the vast majority of users. Upgrade paths are also outlined in that article.

The big question, in my mind, is what does Microsoft mean by the life of the device. A lot of Windows users seem to use their hardware for longer than Mac users (for instance). This may end up being a raw deal for Microsoft, but at least it encourages people to use an up-to-date platform. That may enable them to better market their other products.