Kimkia - 2:15 am on Dec 15, 2011 (gmt 0)
I had left this turned on, but it just got ridiculous, with google plus signs on three display ads per page, plus the one for my own page.
It had the effect of branding the ads with sameness, instead of differentiating, pulling down the quality of all ads. Very confusing too. If I couldn't tell what the heck was supposed to be recommended, I'm sure my visitors couldn't either.
Also, with only so many clicks expected per reader, a non-paying click that doesn't lead to another page on my own site isn't viable.