Chrisitan, a blogger for OK Cupid, works some magic on the raw data from 200,000 and discovers that numbers wise, older women shouldn't have a problem finding men to date online. However, "the male fixation on youth distorts the dating pool," meaning that men do not necessarily want to date someone within their age range.
[A] man, as he gets older, searches for relatively younger and younger women. Meanwhile his upper acceptable limit hovers only a token amount above his own age. The median 31 year-old guy, for example, sets his allowable match age range from 22 to 35-nine years younger, but only four years older, than himself. This skewed mindset worsens with age; the median 42 year-old will accept a woman up to fifteen years younger, but no more than three years older.
These types of preferences begin to have a snowball effect, knocking large numbers of women out of consideration. Even worse is when Christian introduces more information - that men say they are interested in women within a certain age range, but end up messaging women who are even younger.
As you can see, men tend to focus on the youngest women in their already skewed preference pool, and, what's more, they spend a significant amount of energy pursuing women even younger than their stated minimum. No matter what he's telling himself on his setting page, a 30 year-old man spends as much time messaging 18 and 19 year-olds as he does women his own age. On the other hand, women only a few years older are largely neglected.
Part of the gap has to come from culture. After all, despite the unfortunately-named MILF phenomenon, there are very few older women in the public eye who are considered attractive and desirable in the same way twenty-somethings are. Even as we can all point to women who break that mold, the simple idea is that women over the age of thirty are perceived differently than women in their 20s. However, Christian has a snappy answer ready for that one as well:
Many of you are probably scoffing at the idea that many 35 year-olds are as attractive as many 25 year-olds, but there are social factors at work that you might not consider as you go through life making judgments. Most importantly: nationwide, thirtysomethings are much more likely to be married and therefore much more likely to have stopped optimizing their attractiveness. So the typical 35 year-old woman you see out in the world isn't representative of the single 35 year-olds who are still dating and looking good.
The Case For An Older Woman [OK Cupid]