
If you take a look at what's being offered on their site, you'll soon realize... People will do crazy things to make money. I'm not going to list them here because I'll have an enormous list, but I encourage you to browse their site. It will definitely put a smile on your face :)
With the popularity of Fiverr, there's bound to be opportunist who will take advantage of their success. I don't mean this in a bad way, but when a site as successful as theirs, competition is popping up everywhere.
Take a look at all these Fiverr alternatives and you'll see what I mean.
If you plan on using any of these services, like with any new website, make sure you take precaution and validate the company, their TOS and search for social proof that they're site is legit.