I mean pay-per-click sites, I have read from other members that after paying the membership they have not been able to withdraw the profits, this makes me think that if there are sites, that after you pay the membership they block you because they are scam .Not any site asking for membership is scam site. Even for example Google Drive asks for membership if you have used your 15 GB storage to have more space or Dropbox if you have used your 2GB.