The size of India vs. United Kingdom and the relatively similar visit percentage is interesting. Does this mean the UK has a large number of devs or India has a small number?
tl;dr; - visitors are more spread out on the globe, Google is the undefeated referrer, SO visitors love Firefox, Windows, and screen resolutions are getting bigger and wider.<p>Nothing too interesting, really.
iOS will jump up sharply from 0.4% in 2011 if the folks at Stack Overflow make the site usable with that system. From mobile Safari the site is crippled. You can type in an answer, but the formatting tools and preview panes don't work at all.