There really isn't a ton of difference meeting someone here.. or in the personal internet sites. Any one of us could be someone we say they are not.. even here!
HOWEVER.. if you meet someone through a personal service, if you are smart, you take the time to get to know them before meeting in person.. AND you put up smarts when it comes to meeting them the first time. And yes, I have broken my rule and met guys fast.. although usually there was a bottle of whiskey handy and I wasn't being smart..
The nice thing about meeting someone in a place like here is IF you get a chance to meet at one of the gatherings, you see them in a more public way, see how they interact with other people, etc.. it helps to see also how they react to issues on the board. Do they have a quick temper.. etc..
One thing about meeting through the personals and if people are for real.. this is where a web cam is nice. At least you know if you are talking to a male or female.. child or adult..
I've talked to a lot of people online and when you get good at it.. you can figure out who is for real and who isn't..
as for someone being married.. etc.. those are things that are harder to detect..