I wonder if the people who send offensive messages to others in online games are the same who would in previous generations would have sprayed offensive graffiti on walls?

Or perhaps literally stab someone in the face after losing a game rather than impotently threatening to do so online.

I am sure this is the biggest reason. Nothing to talk about more access to education, birth control, ...

It may not be the main reason (which is believe is the tetraethyl lead mentioned in other posts), the effect videogames has had on violence is not trivial. Probably not for "outlet for rage" reasons, but simply because they are a powerful draw on someone's time. Spending time playing video games is less time left for loitering and petty crime.

I submit as "evidence" a bit of anecdata I like to call the "doom curve":

http://blogs-images.forbes.com/erikkain/files/2012/12/videog...