I wrote my senior thesis for college on online dating, and my recommendation would be if you're serious about it, use a paid service. It weeds out a lot of the people because of the cost and it's easier to search too. Most of them have free trials so give it a shot for a week or so and if you don't like it, just cancel it.
This. Met my current bf on an australian site where its free to browse and you only have to pay once to send the first email (the rest of the emails are free as long as their sent within a month). Worked a whole lot better than the free sites because people were more serious about dating and weren't just looking for a one night stand or hook-up.
I definately came across my fair share of creeps/weirdos/crazies (mainly on free sites like POF) but it was definately worth the wait and sifting through the bullshit to meet my awesome bf :)
I actually got one of my friends to try it recently, she was really skeptical at first but she'd been single for about 2 years and figured why not give it a go. She's currently seeing a guy she met on there a couple of weeks ago and couldn't be happier.