Erm, no, again
Have to add that I'm using Guardian Soulmates at the moment and finding it very good so far (still chatting to girls in bars as well though, it's not an either/or situation) . It was recommended to me by two separate (female) friends who both found their current partner on there.
Haven't come across any "professionals" or import-a-bride scams, but hey, maybe I'm not looking at the profiles of girls who's pictures are the kind you'd see stuck up in a phonebox.
Free dating sites on the other hand are stuffed full of scams because there's no barrier to entry, bar a working e-mail address. Once you start charging the number of scams are of course going to go way down.
For the record, I don't read the Guardian - in fact I don't think a lot of people on there do. It's just one of the more popular sites.
Also - People sneering at online dating on a site full of nerds? Know your audience people.