I have been searching, unsuccessfully, for an Ad Server that has the following:

- Native Advertisements
- Real time bidding for CPM/CPC
- Keyword targeting
- Context targeting would be great, too
- Advertisers' login where they can view their stats and create their own advertisements
- Integrated, automatic billing

All to manage advertisements on a single website, or small group of websites that I run.

I want to be able sell the advertisements directly to the advertisers who want specifically to advertise on my site, not to a general pool of advertisers (so AdSense is not suitable)

Adzerk so far seems something like I'm looking for, but the website is not so explicit on features, so I can't tell...

Does anyone have any recommendations on a service that can do what I'm looking for?