I have a blog that gets around 4000 visitors a day. Would it be good to serve CPM ads from, say, fastclick, or casale or burst or tribalfusion on the blog? If someone has experience, how much does this bring in each day/month. Also, which one of these is the best with respect to income and the annoying-ness of the ads, and the system? I am wondering if I should bother with CPM ads at all, or stick to adsense. Finally, is it a violation of the adsense TOS to display CPM ads of the kind I listed above on the same page as adsense ads?
I don't think placing them together is a problem from Google. You are actually doing Google a favor helping them earn money.
Placing them together is not a problem, but the CPM ads has to be above the fold with most of the ad formats. This will mean you will have to really put adsense ads below the fold if you don't want your blog to look to cluttered with ads. Personally if you are making over $1 ecpm with each ad format from Google, then I think it would be best to stick with Adsense.