redfly,
just to follow up on your post - I've been playing around with a few CPM networks now.
I know this is a very open question (and depends on niche etc) but what would the average CPM rates be out there? Is this question even possible to enter. Saw some laughable eCPM rates from some publishers so just wondering am I expecting too much...
It completely depends. First off, it will depend on the pool of advertisers for your market. If you run a MySpace resource site, you are going to get crappy ringtone advertisers paying pennies. If you are running a forum about applying for a mortgage with 20k uniques a day, you're in for a MUCH higher CPM.
Then there is the network. Tribal Fusion for example have minimum rates and a minimum spend of $20000 a month I believe. They also only select sites on a manual review basis.
Then there are networks that allow you to set your own minimum CPM where you can only serve ads at that rate or higher (TF). When inventory is full, it gets passed on to the next network in the chain.
Then there is volume. Again, depending on your market and traffic, you are going to run out of ads to be served. Then what? Then you have to settle for the pennies. Thats where CPX and adbrite come into play.
I hope that has helped. If you have any other questions, please let me know.