Windows 10

Windows 10 is the successor to Windows 8. Version 9 was skipped, probably to prevent confusion in software that "sniffs" versions and might mistake anything starting with 9 for Windows 95 or 98. For a change, Microsoft actually officially identified this version with internal version numbers starting with "10.", matching the number used in the marketing, unlike Windows 7 and 8 which used "6.x" versions. Apparently they're not worried about 10.x being "sniffed" as version 1, since nobody ever used Windows version 1. A "Windows 30" some day could bear risk of being mistaken for the popular-in-its-day Windows 3.x versions.

Windows 10, which was heavily pushed as a free upgrade for Windows 7 and 8 users, has been regarded by users as "not quite sucking as badly as Windows 8" in the user interface area (it mostly returns to classic interface styles, with that ugly Metro stuff showing up mostly in the "Start" menu... but at least there actually is a "Start" menu!), but there are many concerns raised about all the privacy invasions built into it where all sorts of information is sent automatically to Microsoft unless you specifically opt out of it (and possibly still even then). You need to agree to a good deal of privacy invasion just to get decent functionality in Microsoft's new personal assistant (and answer to Apple's Siri), "Cortana".