Farmville and Mafia Wars are full of teenagers, you're only half right. The average player of social games is actually younger than previously believed, according to a new study, but a little older than teenage: 29 in the US and 27 in the EU. That's an interesting conclusion, especially since the average gamer is actually a little older than that (s/he was 30 a few years ago and has been getting steadily older since then), and most people believe that social gamers on Facebook tend to skew even older.
This survey by GamesIndustry.com, however, goes against that grain, and claims that while there are more females playing these games than males, they tend to be younger than expected. Peter Warman of that site says that the reason for this is that most such surveys don't poll any lower than age 18: "It is therefore not at all surprising that their average age is extraordinarily high ... Data from kids and teens is vital and should always be taken into account."
If these surveys aren't representing anyone below age 18, then it's possible gamers, especially those playing social games on Facebook and elsewhere, are even younger than anyone's guessed previously.