The most common form of adult content is a categorized list (more often it's a table) of small pictures (called "thumbnails") linked to galleries.
These sites are called a Thumbnail gallery post (TGP).
On the Web, there are both commercial and free pornography sites.
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.
Pornographic images had been transmitted over the Internet as ASCII porn but to send images over network needed computers with graphics capability and also higher network bandwidth.
These files could then be downloaded and then reassembled before being decoded back to an image.
Automated software such as Aub (Assemble Usenet Binaries) allowed the automatic download and assembly of the images from a newsgroup.
Internet pornography is any pornography that is accessible over the Internet, primarily via websites, peer-to-peer file sharing, or Usenet newsgroups.