- over 50% of mobile (tablet/phone) market is dominated by Linux (android, sailfish, kindle os, maemo, meego)
- almost 100% of low end tablet market is dominated by Linux
- huge amount of smart watch/tv market is dominated by Linux
As there is no accurate way to tell the actual market share based on user agent alone, I have issues believing these numbers since
A) There are several different services doing this, using a limited selection on different sites.
B) People may be disabling requests/scripts to prevent tracking from advertising firms.
C) Some people spoof the user agent by default.
As for a guess for if they were accurate, I personally would guess because of Google and its partners' Chromebook success.
Steam would most likely has nothing to do with an increase in GNU/Linux usage, as the vast majority of its users would stick with Windows, as they already know how to use it and that's where the vast majority of games already are.