These sites are called a Thumbnail gallery post (TGP).
As a rule, these sites sort thumbs by category and type of content available on a linked gallery.
Sites containing thumbs that lead to galleries with video content are called MGP (Movie Gallery Post).
The method was also used to disseminate pornographic images, which were scanned from adult magazines.
On the other hand, Link Lists have a larger amount of unique text, so that helps them to improve their positions in search engine listings.
Top Lists are linklists whose internal ranking of freesites is based on incoming traffic from those freesites, except that freesites designed for Top Lists have many more galleries. Another free source of pornography on the Internet are the Usenet newsgroups that were the first home to such material.
While the study's authors note this increase is "smaller than conventional wisdom might predict," it's still quite significant.
Children born in the 1980s onward are also the first to grow up in a world where they have access to the Internet beginning in their teenage years, and this early exposure and access to Internet pornography may be the primary driver of the increase. Pornography is regarded by some as one of the driving forces behind the expansion of the World Wide Web, like the camcorder VCR and cable television before it.At this time the internet was mainly an academic and military network and there was not widespread use of the internet.