I've always wondered what celeberies do on their spare time. They're people, too, so I've always wondered if they play Xbox, PlayStation, etc. even though they're probably busy doing celebrity stuff. I wonder how many people have played games with famous people without realising it.
For some reason I don't find this that surprising at all. She grew up right around when computers really started to come forth as the big-thing. She was 17 when the original release of WoW was given... And she was almost always on the road. You could play it on a laptop at that point I'm sure, and be active and communicate with people without them knowing who you really were (as she mentions in the video) - which is a real upside for a giant star (she had already been on That 70s Show for 3 years and played the role of Meg Griffin on Family guy for 2 years when WoW was released). It's time to get away from those people you know IRL and time away from being this big giant star that's always being followed around by the ratarazzi.
I'm sure she also played Star-Fox 64 and all the other amazing Nintendo games from back in the days as well.
I think its a lot different for people who grew up being famous as oppose to people who already grew up then became famous. I think mila was 15 or 16 when she started doing "thats 70s show" so i don't see why she would stop playing video games or anything else because shes famous. Now someone who is 25 years old and has been on tv sets and movie sets since they were 8 years old might not have been exposed to as much popular culture.