My observation is that online dating not only works but has by now become totally mainstream. I keep hearing about couples which met on the Internet, in fact I would say that this is true about 100% of the weddings I'm attending this year. It's no longer something that warrants even a lifted brow. My perception may be biased by living in the Bay Area, but even if so, then it's just a matter of time.

This does not mean that the dating sites are particularly good right now, just that the demand is so great that people are willing to suffer the poorest UIs to get to the good stuff.