Flickr/Yahoo! have taken some steps related to allowing users to monetize their photos over the years. There's been an agreement with Getty and they've done some other things as well. At its heart, though, flickr started out with very much a community orientation and, while they haven't necessarily done the best job of it, they've maintained more of a community than a commercial flavor.

Aside from the young, female, and attractive though, it's pretty hard to commercialize a flickr presence in any significant way. Even microstock sites which are explicitly about selling aren't a great source of income for most.