Why doesn't Sony advertise the PS3 in NA much?

[Bodhesatva]

This isn't something I've noticed. I've seen as many ads for the PS3 as I have the Wii and 360, but it's important to note that it's cyclical: when a big game comes out for 360, then I see more 360 ads than anything else, and so forth. When MGS4 came out and for several weeks afterwards, PS3 dominated the advertising in my neck of the woods.