There are two kinds of porn sites: commercial and free porn site. People tend to choose the free one for they do not need to spend any cent to enjoy porn videos of mature sex, amateurs, professional, etc. The adult content of porn sites that usually known are TGP/MPG, Linklists, Usenet, and Peer-to-peer. TGP/MPG derived from Thumbnail Gallery Post/Movie Gallery Post. So, the sites will be in the form of thumbnails that are linked to the galleries which is sorted out based on the category and type of the content. The advantage of using TGP/MPG is the user can get impressed by the pictures without visiting the site.
One of free porn site is BangYouLater in which the users have to be 18 years old or older. The site offers various kinds of porn videos that are offered based on the category including amateurs, anal, Asian, BBW, Big Tits, Blonde and many others. The users just have to visit the site, register (usually for free) and choose category based on their preferences. If we talk about mature sex, the porn site will give videos of only mature women with various categories such as mature sex movies, mom tube, granny I fuck you for money and many others.
Back to the adult content of porn site. The second type of site that delivers adult content is Linklists. Differs with TGP/MGP, this site only display the links in the form of texts, not thumbs. Linklists have a wide range of unique text so it eases them in searching engine. The next site that delivers adult content is Usenet. Compared to two previous sites, it has poor organization in content and full of spam. In this site, commercial software and websites can be accessed so the users can browse the images and videos on what the so called newsgroups. The last type of site that delivers adult content is peer-to-peer. It refers to the distribution of free samples by using peer-to-peer networks.
If we compared between male and female users who are visiting porn sites, males will contribute bigger than females. Then, there are many formats of internet pornography such as image files which usually scanned from magazines or other sources and uploaded in the website. The second format is video files and streaming videos in the form of MPEG, WMV, and QuickTime. The third format is webcams that usually in the form of FLV.