Some websites collect data on visitors to their website. One bit of gathered data is the address of the website the visitors came from. This address can be faked, and referrer logs are increasingly being filled with "visits" from sites with innocent-looking addresses - but they are actually porn or herbal medicine or other spammy sites. The spam might not be noticed unless they are in the top 10 or top 20 visitors of a site -- so they relentlessly visit a site in order to push their address to the top of the analysis chart. This is referrer spamming.- Category ID : 55625