Is it possible to organize high-level targeting with your own hands?

Question

Internet advertising

We are thinking of creating our own banner network. In terms of parameters, none of the existing paid / free solutions suits. Is it possible to somehow get and use google'a data about the user in order to improve the targeting of our network?
That is, for example, I know what subject the user is on the site now, and I know where he comes from. But is there any way I can get more targeting information?