I've been advised that once a site reaches a certain level of traffic it's possible to get more lucrative ad providers on board that give better return than AdSense.
For a reasonable sized ad above the fold (for example 728x90 or 160x600) what sort of CPM can we expect?
What level of traffic do we need to achieve before we become attractive to these bigger fish?
Thanks in advance for any insights you can share, Gavin