Of course, he's only 5, so we've put restrictions on it. No more than 1 hour of technology a day (that includes TV viewing, his other computer games, and WoW), he's only allowed to make Tauren and Blood Elves on our Horde server (which we decided on today after he'd made an undead warlock and my husband and I looked at each other as he played through some of the starting area and went "um... no... not comfortable with that level of dark and evil for our 5 year old... and the cannibalism to regain health, which he was then acting out in imaginary play afterwards... no... don't want to explain that to his Kindergarten teacher"). Trade is, of course, blocked, and mature language filter is on... and he doesn't play if I'm not in the room.
Also... as with all his computer games that are, really, FAR higher a level than he's supposed to be playing... he has to figure it out on his own. Mummy and Daddy will occasionally give him pointers, but he needs to work out how it goes on his own. This includes reading and doing quests... and the language level in WoW is really quite sophisticated, with a wide vocabulary being used, and with turns of phrase and idioms used that are really very challenging. Technically, the reading is at the frustration level for him... but his level of engagement is so high that he will soldier through with only minimal prompts from me, and without giving up and/or asking for my help constantly. It's pretty awesome. He reads REALLY well for a Kindergartener to begin with... and this is certainly not slowing the process down!
My husband is going to make a Panderan to level exclusively with the boy. Good father-son bonding time. :-)