Here's a good case example of what fraudulent profiles and pay-for services can bring you. (Need to split this in two as it got a bit long.)

Once upon a time (2002-2009) there was a social networking provider with mobile billing called SMS.ac. (And it's fun that "SMS.ac" is an anagram for "scams".) They used fake profiles in abundance, and would bill you for notifications sent to you from received messages. Some of their employees would use these bogus profiles for sending see more "I'm interested in you" messages to members, who would then pay for the SMS notifications received.

Having received a volley of invitations (in 2006), I looked them up, and checked out how their "send free SMSes" setup worked; it didn't actually work for my locale, but in the process I had signed up to pay for all sorts of SMS notifications tied with the account I had created (and it was justified in some very small print that was tucked away somewhere). I wrote about it at some length on my site (http://www.codewallah.com/smsac/), and then received a cease-and-desist from their local advocate in both e-mail and snail mail. In their view, I "violated their trademarks" with my screenshot and mentions of their company name; it was of course nothing but an obvious attempt to intimidate me.