I have grown to really appreciate mybloglog, I think it's a totally awesome tool. Also as an internet marketing professional I think that Yahoo! got mybloglog for a song. With the distribution this widget gets I am sure there are some quite incredible opportunities for mybloglog to earn millions a year in revenue. However 2wks ago I added mybloglog to my paper airplanes site to see if I could create a community around that site which would be totally awesome. With c. 150 000 unique visitors a month it seemed like a good idea.
The above graph shows my daily CPM for my left hand adsense skyscraper since the start of 2007 (although I have removed the absolute amounts from the left axis). On adding the my blog log widget (directly below the adsense ad) the CPM dropped dramatically and interestingly as the below graph shows the CTR % stayed the same through that period so effectively for some reason my average CPC dropped.
I don't know if it is google detecting there are images close to the adsense ad, I don't know if it's mybloglog changing Google's opinion of my page quality for the adsense crawl or what (it certainly isn't people clicking on mybloglog and joining my community :( - it didn't work for paper airplanes, that's why I took it off) but somehow there was a directly correlated change both when I added my blog log and when I removed it on my CPMs through adsense. I'd love to hear if anyone else has seen the same or if I am just a screw up :)