Through some raddom webbrowsing, I found the site above - the article, is highly biased and makes a lot of assumptions, but the discussion was interesting.
For a start, as somebody who extensively used online dating for the guts of 7 years, I would strongly, heavily, advise anybody to be ultra-cautious. I dated both men and women (ok for a few years I was still trying to do the bisexual thing). Also I did actually end up with a flatmate through online - flatmate from hell I should add. The men were all completely and utterly wasters - their selfishness seemed to know no depth. Most of the women I met were varying degrees of "unstable" from mildly disturbed to pretty much hysterical. Lots seemed to have little or no life. Social class, interestingly, was varied as early on a lot of people online were students.
First of all be warned that a lot of people who go online to build up their relationships do so because they have a lot of time on their hands. Many are already in a relationship. But many are quite normal people who are exhausted with the tiresome dating scene of circles of friends, bars and clubs.
Much of the criticism of online dating is based on the false premise that people who date online are anti-social computer nerds who have no lives outside of their computer use. This was the case to some extent around 1994, but nowadays many computer users are not very technically literate. (Back in 1994 I was was chatting online using irc2 running on the college's DEC Alpha system via a dumb terminal connection. It was purely text based - and exceedingly powerful. Back in the good old days before security holes there were a few ports open that enabled us to do that. Don't laugh at my nerdiness - I was a musicology postgrad!) Many people are curious by the opportunities offered, and a lot of people assume that they will find online dating less harsh.
The reality I've often found is that most people you meet online tend to totally drop you again just as quick. If somebody did that on you in person they'd be regarded as pretty low. Much of the problem online circles around two points - that this isn't "real life" and due to a lack of a social circle, nobody else important to the person is going to know. So you can dump people and get away with it, because your friends don't even know you've done it. Men pretending to be women used to be a huge problem on sites and chat rooms for gay women - these have dropped dramatically as many gay women now go for gay branded sites - men who will pretend on a mainstream site won't do the same on a gay site as they are often as homophobic as they are deceitful and don't want to attract other men!
Now on the gay womens scene in Ireland what has happened is that the 2-degress-of-separation applies online, so I find that somebody who contacts me via email or on a chat room is HIGHLY likely to be either somebody I know, or known by somebody I know. There is a high degree of interactivity between online/offline interactions and so dishonesty is more difficult. I still managed to end up in a relationship with one of the most dangerous gay women in Ireland, mind you so I'd give you the following advice. This is built on several years of online dating culminating in a 1 year relationship that spelt disaster for me, and ended my online dating career.
1. Meet as soon as possible. In a public place and make sure a friend knows where you are going. More deceitful online daters are dependent on a culture of secrecy. Meeting will give you more opportunities to assess them as a person.
2. Be very wary of anybody who lies. Chances are that these may be very persistent and lie about different things. Get out quick.
3. Trust your instincts on meeting somebody.
4. Try to get to know people around them. If they deliberately do not let you get to know them in context - run!
5. Watch out for gold diggers - folks who are not working frequently desperately seek somebody who is well heeled in order to support them. A lot of these will spend hours on the net seeking successful people. These are highly dangerous individuals.