You'd better believe it. We were staggered ourselves when the number of people registered kept rising and rising. People tend to be shy face to face, but online, there's no stopping them.
Providing you use your common sense, it's no more or less safe than meeting a stranger in a pub or club for the first time. Some of our members are very sexually active, so it is always recommended to practice safe sex until you know someone well enough. The first time you meet someone, make sure it is in a public place until you get a feel for each other. Women should never invite a stranger to their home until they are comfortable.
YES and no. You can join, look at profiles and pictures and hang around completely free of charge, but if you want to start actually arranging casual sex meets then you will need to pay for a membership upgrade - it's less than a take-away and a couple of pints or glasses of wine and a hell of a lot more fun.
Yes, couples are actively encouraged to join and in fact, if you are a male looking for group sex it will be a big help as many groups prefer not to invite single men to their orgies.
It takes all sorts and with so many people online, it's highly likely that you will get to fulfil at least part of your fantasies. Either that or you are one crazy fucker.