I noticed something strange about stackexchange while doing a Google search. In one hit to stackexchange with a really odd tag stack (see screencap). Thought you'd want to know there's a bunch of completely unrelated tags there, like "travel" and "christianity". Also, I noticed that most stackexchange hits didn't seem to have that tag stack? Seemed odd, so here you are:
the search URL: https://www.google.com/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=math+language+blender+driver+expression&*
the specific link with the weird tags: https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&cad=rja&uact=8&ved=0ahUKEwjfnOL70KbSAhWD1CYKHWrfDPoQFggmMAI&url=http%3A%2F%2Fblender.stackexchange.com%2Fquestions%2F8135%2Fusing-a-scripted-expression-driver-to-combine-two-angles&usg=AFQjCNH8ZOT_dyP5s05x56KPz-00OoCyfA&sig2=sSzDT-QE_O8xm40mjOecsA