Chris13 - 2:54 am on Aug 3, 2013 (gmt 0)
A lot of publishers are seeing the exact same thing as you. For me it has nothing to do with sources of traffic either. I do zero link building and my traffic either comes from search engines or returning visitors.
Set to no interests based ads, still showing them.
Btw, I queried this with adsense tech support. The setting doesn't mean what you think. It doesn't turn off interest based ads. Here's the exact answer I got to that question.
You can opt out of showing ads that are based on user interest and demographic categories (for example, 'sports enthusiasts' or 'inferred age: 18-34'). In turn, Google will not use visitation information from your sites to help create interest and demographic categories. However, you cannot opt out of showing ads to users based on their previous interactions with the advertiser, such as visits to an advertiser's website.
While Netmeg is having good results with adsense, and I'm sure there are many others who are as well, many are not and there's no real explanation coming from google.
I believe that Netmeg has reduced the number of adunits adsense is getting and replaced those with direct sold ads. That would explain the higher CPC because of the way adwords bidding works.
I went a slightly different route. I cut the number adunits I give adsense and replaced them with media.net ads. Less pay = less leased space received. I'm planning some direct ad sales later this year.