it's not about being particularly special, obviously,
it's about being just one incredibly small subset that happens to have non-average characteristics. i would say the same about reddit, or any other 'special internet community'.
if you actually want some analysis to uphold the incredibly obvious concept that 2p2 would deviate greatly from internet-wide CTR...
PER THE REPORT YOU LINKED, females are significantly more likely to click ads than men. twoplustwo is 65% male
, while facebook is only 45% male.
additionally, twoplustwo's age demographics are way way way off from facebook's averages. as you can see in my links above, twoplustwo is
8% Under 18
These values for Facebook are
26% Under 18 (+18%!)
24% 18-24 (+14%!)
18% 25-34 (-14%!)
13% 35-44 (-18%!!!)
since gender and age are some of the clearest determinants of CTR, as outlined in your own report
, I expect these monumental deviations from site to site would be enough to convince you of the idiocy of why 2p2 would be an incredibly poor sample to make judgments about facebook CTR from.