More accurate than all the Sociological faculties at every major university.

From the Volokh Conspiracy:

OKCupid’s datamining blog is a source of amusement, politically incorrect insight, and horror in equal measure.  But what strikes me is the enormous power that comes from the democratizing of data-mining.  It will change the world, just as Google did when it democratized clipping files and newspaper morgues.

The people at OKCupid do a nice job of presenting the data without shaving the data to fit social pieties.  Some of their observations are amusing, such as the finding that everyone - men and women alike - make themselves two inches taller in their profiles. 

Some are counter-intuitive, such as the fact - Ladies, listen up - that skin "sells" for women on internet dating sites, and it sells more the older you get.

Alright, I'm not sure how that last point is "counter-intuitive."  But that's the data.

This one answer the question my 12 year daughter asked me about why society thinks it is "ok" for men to date younger women, but not for women to date younger men.  I gave a lot of folderol about arbitrary social conventions linked to evolutionary psychology, but OKCupid has the data and an explanation:

A woman's desirability peaks at 21, which, ironically enough is the age that men just begin their "prime," i.e. become more desirable than average. Following that dotted line out, you can see that a woman of 31 is already "past her prime," while a man doesn't become so until 36. As we mentioned above, after age 26, a man has more potential matches than his female counterparts, which is a drastic reversal of the proportion in young adulthood, when women are much more sought-after. Because men's dating preferences skew so young, and women's are age-equitable, men peak later, and have a longer plateau of desirability, than women.

Also, if you want to know the chances of whether you will "get lucky" on the first date, find out if you date likes the taste of beer or whether they would find the prospects of nuclear war "exciting" since "in the post-apocalypse, there are no second dates."

If you are on the front-lines of the "the Dating Life," OKCupid is an essential survival resource.