I think this is the reason: http://www.cameronmoll.com/archives/2006/12/gridding_the_960/ http://www.cameronmoll.com/archives/2006/12/gridding_the_960.... 960p

I think this is the reason: http://www.cameronmoll.com/archives/2006/12/gridding_the_960/ http://www.cameronmoll.com/archives/2006/12/gridding_the_960.... 960px was the "standard" for so much time (before RWD was a thing) that I still use it as the default width when designing new stuff. Maybe this is a bow to the old masters of our craft.