A friendly MSN adCenter rep called me today to get my feedback on adCenter. Well, as you can guess, I regaled her with an hour's worth of ranting. In exchange she looked at one of my adcenter campaigns and gave me a tip (paraphrasing here):
AdCenter likes small, relevant ad groups. Break up that big keyword list so you don't weigh down the overall average CTR with the speculative long-tail terms.
This is something obvious that I should know. It's true on Google and Panama as well. Make small adgroups of like terms. But apparently, that explains some of the lack of traffic in a comparison test of AdWords, AdCenter & Panama I wrote about.
So I'm going to try it and see how it works. I'm glad they called me - it's nice to be able to write something positive about Microsoft once in a while.