deadsea - 10:25 am on Mar 15, 2013 (gmt 0)
My site is clearly in the group of 5000 that had "nessie" arrows removed. On a scale from 0-100, my RPM has been all over the place in the last few months.
November 2012: RPM holding steady at 50
December 12, 2012: RPM shoots up to 90. I concluded that Google had introduced the nessie arrows onto my site that day.
December and January: RPM gradually declines from 90 to 65. I assume that users are becoming accustomed to the nessie arrows and clicking on them less.
February: RPM is steady at 65
March 9th: RPM falls to 40. I find out here that nessie arrows were removed from my site. Both my CTR and CPCs fell on that day. (I made no site changes in the weeks leading up to this.)
On March 9th, only my desktop traffic is down. My smartphone traffic is converting just as well, if not better than before. Nessie arrows are still appearing on smartphone and tablets, but not on desktop.
Targeting of ads on the desktop seems to be totally broken. Testing fresh profiles on a variety of desktop browsers shows ads for cars, education, insurance, and laptop computers. Nothing that is actually in my niche. Ads on smartphones and tablets show ads related to my niche.
(Does this nessie update deserve its own thread here?)