After these organisations allowed domain names to expire, usually when they decided to use an alternative name, they discovered their old domain names pointing to porn sites. The porn sites profit through advertising revenue which increases in proportion to the traffic they generate.
For the porn sites, they have control of domain names to which several other sites already link, albeit the sites are unaware that they are now sending users to view porn. This provides the porn sites with both direct traffic from unsuspecting users clicking these links, and with rankings on some search engines. Among the domain names now pointing to porn are those formerly used by the International Lutheran Woman’s Missionary League and the Ohio State Senate. Often, the names taken are those not containing trade mark rights which make them difficult for the original owners to recover.
In response to the problem, internet filtering company N2H2 is promoting a system which scans the internet, identifying web sites that previously contained innocent content but now contain porn.
When these new “stealth porn sites” are identified, N2H2's customers can have the sites blocked by filter software. According to the company, its scanning system adds more than 3,000 new porn sites each week to its database, “a number of which pop-up on the internet under rather innocent domain names.”
According to Snapnames, a company which deals in expired names, approximately one million domain name registrations lapse each month. Most get purchased very soon after becoming available.