This probably works if you're an average guy looking for an average woman. In that that case, you are most likely to be compatible.
It doesn't work so well if your interests, tastes, or personality are off the beaten track, however.
I have a lot of unusual interests and prefer to find women who share them. So my success rate at just randomly rolling the dice and having women just randomly roll the dice in return (such as with short profiles or speed dating) has been pretty low.
What has worked reasonably well for me has been having really detailed profiles. That way women really know what they're getting when they contact me, and I they're likely to be women who self-select to be relatively compatible with me by the time they reach out -- though there's always the chance that we just won't have much chemistry when we meet in person, and that tends to happen more often than not (though not as often as when I meet random women at bars, clubs, work, or wherever).
I've also never posted pictures of myself (though I have sent them upon request). That, along with my interests, helps to select women for whom looks aren't critically important, which is important for me (despite being above average in appearance myself.. I just don't want to be sought after primarily for my looks).
Another thing that's helped enormously is to find some way that immediately sets you apart from the crowd. My profiles/personals effectively scream "freak!" and that attracts freaks in return -- which is exactly what I want. That can be a huge turn off for the normals, but an attraction for people who share my tastes.
Not to get too philosophical, but I think it's important to somehow signal to others that you are like them. That's why dress codes for subcultures are still so important. They're systems of signaling that you share common tastes, world outlooks, interests. The same has to be done on dating sites, whether you do that through a pic of your biker tats or punk haircut, or (as in my case) by just detailing your interests.
Personality is, of course, also important, and that can come through your writing (or pics). I still have to work on that.. maybe take a creative writing course. My profiles are definitely way too dry.