More partners doesn't mean more sex. Not if you spend lots of time between those partners. If you sponsor enough of such surveys and look for enough "results" you can probably find one which suits your advertising. So iPhone users have more partners . . . and Mac are really pleased with the publicity.
If you follow the OK Cupid link in that article, it tells you things about attractiveness of photos. For example SLRs and Leicas take the best photos. Or more likely people who buy SLRs or Leicas (the latter meaning millionaires ) are better at taking photos than those who simply wave a phone at somebody and push the button.