I have nothing against SF at all but this kind of sounded like a call for attention. They talk about this data like its the final word on the subject but leave out so many other really popular resources where people get their apps like App Stores, Package Managers, GitHub, etc.
And what OS wars? This is 2011 not 1997. The OS makers are competing but they're not trying to be all things to all people like in the old days. We've got Linux distros for all types of users from sys admins (Arch, CentOS) to casual users (Ubuntu and other Debian based distros). The Mac has its own uniqueness that appeals to a broad audience and some people want their old standard, Windows. Some are gaining ground, others losing, but it's not like 10 or 15 years ago where people were looking for a winner. Some people are still and I'd say that's kind of dumb and jingoism has a bit to do with that.
This article should have had the title "SourceForge Sees Major Increase in Downloads from NameofOS". I call link bait.