[the_watcher]

Google knows more about what users intend to do based on what they search for. Facebook knows more about individual likes, activities, interests, etc. Facebook likely won't ever compete with Google's AdWords business (barring the real possibility of a new product somewhere in the future). But in display advertising, building a user profile is more valuable, as it is a much less intent based ad. It's a fact that Facebook is better at this than Google, because Facebook display performs markedly better than Google Display.

> Facebook knows personal details, mood, etc for people who explicitly choose to share these things with their friends, or participate on Facebook in other ways.

Facebook knows so, so, so much more than just this. Facebook knows about events you go to and are interested in. Facebook knows the type of content that you are most likely to click. Facebook knows what you are most interested in.

[brianobush]

I don't know, I post primarily girls hockey stuff, but myself am interested in so much more. This probably varies per user, but my behavior on google properties probably is much more telling.

[the_watcher]

It's not just about what you post. That's only a tiny variable. It's also about what you have liked, the activities you've done in apps and other sites with data-sharing agreements, and what you click on. Demographics, interest, and personal characteristic targeting is far better on Facebook than anything you can buy on Google Display. I'm a buyer of both, and the difference is staggering.