Our system can handle most of what you are looking to do, just a matter of what approach makes the most sense for your use case. Our system allows for ad requests to include arbitrary data for reporting, be it a URL or identifier. As for reporting on this data, reporting is typically 1-5 minutes behind the event (impression, click, or conversion).
So, based on the three requirements:
1. Setting up ads can be done through our interface manually -or- you could generate an import routine layered over our API.
2. Geo-targeting is built into our system
3. Tracking impressions to a website or URL is possible, just not real-time but close to real-time, without the need to create a channel or zone for each site.
What other requirements did you have? What type of creative(s) are you looking to server?