Does anyone know anything about Targeted Advertising?

[Makeveli]

Does anyone know anything about Targeted Advertising?
I've heard a lot about it, Do I need to buy something like an Ad Serving client?

Or can I do it all for free...?

My site did/Will get more than 10 Million Hits/month and have a couple thousand members, so I think it was/Will be big enough.

I know PHPNuke can track banner impressions, so is that like what an Ad Serving client does?

I'm a newbie and very confused!

What's a good CPM Rate for Targeted Ads?

[Makeveli]

I forgot some stuff...

Do I need to take stats like:
-Age
-How long they're on the site
-Buying Patterns
-Location
-Etc.

How would you recommend taking those? A poll/Survey?

I know i'm forgeting some other stuff too, thanks for the help!