If you're talking about sex personals sites, lonermutant, I'd disagree. I use them when I've got the urge, and often pick off around three guys a week when I'm single. None of them satisfy so none are invited back. It's like shooting fish in a barrel. Mind you, the gender ratio is about 11:1 male to female on most larger sites.
Other personals sites mainly yield men who are looking for sex but don't know how to say it politely.
Bugger the personals sites, find something social where the focus isn't finding a partner, like wrongplanet.net. How many people have approached me with offers of coffee, backgammon, chess and other silly fun things to do together, whilst adding coy things to the conversation?

Mojo. Develop your mojo!
The problem is that I live in a small town where most single women are single because of the way they look and the women who use "sex-only" dating sites here in Norway are either teen boys looking for free porn posing as bi women or prostitutes.
When you're a total outsider like me in a tiny town you can't use a dating website, it equals suicide.