More and more people

 1/ What do you think it is that makes more and more people register on these dating sites?  
Amongst other things, there are three main advantages: the financial savings (you get access to lots of single people for a few pounds), the emotional savings (you're not directly  exposed to the watchful eyes of others and you don't lose face if you're rejected) and time saving (you can flirt with loads of different people from the comfort of your own home, in your own time!).

2/ Has it had an influence on relationships between men and women?  
Because of an increased pragmatism regarding love, we act a bit like consumers, and there's a huge market out there for single people. There's some cynicism and suspicion because on the net you don't owe anything to anyone: you read your emails, reply to who you want to and then disconnect.  

3/ The Internet offers a large choice and makes it easy to pass from one conquest to another. Some women think that they could become victims. Is this true? 
I think that people are capable of detecting the smooth talkers and those who tell lie after lie. Few people are all that naive. Besides, we're all-powerful on the net, disconnecting and getting rid of unwelcome people whenever we like. That's reassuring.