its an acronym for a cam girl website.
Cam girl websites are the latest thing in the development of sex lines. Previously you had to pay £2 a minute or whatever to listen to some house wife talk dirty to you down the phone who you had no idea what they looked like.
Now with cam girl websites, you can see them, much as you can with babestation and other 9xx channels on Sky, but they are average girls on the street, just using the webcam on their laptop. You can get free shows, or if you tip them tokens (which you buy from the website and the models redeem to get paid cash each month) you can get a private show.
The prettier / dirtier you are the more tips you get. The more tips you get the more money you get. Its quite sad really as a lot of the girls on there are there purely for money. Its effectively like tipping a stripper, but done over the internet.
You get the odd few who go on for a bit of fun and never stay around, but there are some very determined ones on there trying to make a living doing it.
MFC is just one of many of such sites, and as the OP has discovered they are a great way of eastern european women geting a ticket into the UK from some rich guy who is willing to spend hundreds of pounds on tips for them. And ultimately thats what it all comes down to - money.