The following cultural divisions have allegedly been drawn in a recent "preliminary draft" of research from Danah Boyd (a PhD student at UC Berkeley, which is reason for skepticism on it's own.) It'll be interesting to see what the final report looks like, but the preliminary results are worthy of testing by savvy New Media marketers.

From our experience with 30-plus crowd in the major social networks, MySpace is home to more direct sales/network marketing types while FaceBook tends to be more college grads (but mostly corporate worker bees.) LinkedIn and eCademy are where you'll find more business owners and high level executives.

We should keep in mind that Facebook started out being only accessible to college types.

Good point Shaine. Something I'm sure the report will not include is the impact of the site's guiding vision on the cultural divisions in each network.