Some of it is trustworthy - like from Facebook, Google, or Bing - but some is really shady. Well, of course, all the "cheap traffic providers" are motivated to deny using bots, but we can't really be for sure! Anyway, a lot of the traffic comes from crappy sources - where the visitor might not really be wanting to come to your site that much; in other words, the motivation matters.
What is your experience with such companies? Have you thought about using them? What's your impression?
What is your experience with such companies? Have you thought about using them? What's your impression?