Things you don't always think about. According to a study by Pia Sundqvist and Liss Kerstin Sylvén, games like WoW are causing boys in Sweden to pick up English faster. Essentially, by playing multi-player games where the language of choice is English, the boys are learning the language faster in order to increase their proficiency at the games in question. There's also discussion of WoW in Schools, a program designed around using the MMO to instruct.
What's interesting to me in the Slate article is the reference to situated meaning, the concept that something is easier to learn if it has a context provided by actions rather than simply being told its definition. It's easier for people to learn what words mean if they're using the words to mean things, rather than simply reading what they mean. That fascinates me - it actually makes me want to start playing WoW on a server where the language is one I want to learn. Maybe I need an EU account.
For the complete article, head over to Slate and give it a read.