There's ageism too. I find it very weird that people immediately assume that just because somebody is over 35 that they'll be less technically literate than somebody in their 20's (especially as I'm acquiring grey hairs at a steady rate :-)

A few years back I hired a very clever guy to do tech support for the company I worked for at the time. Very clever guy - and a serious Linux geek. Much more knowledgeable in that area than myself. Yet several people assumed that he was less technically literate than I was just because he was twenty odd years my senior. Scary.