Adult videos come in a vast array of lengths, subjects and categories. Some are much more graphic than others. Some feature complex plots, storylines and dialogue, while others are nothing more than a collection of XXX hardcore sex scenes, cum shots or blowjobs. If there is an established fetish or kink out there, there has no doubt been a video made about it. Probably several.

Feature Videos
Feature videos are the big budget extravaganzas that star the biggest stars in porn, like Jenna Jameson, Chasey Lain, Janine and Tera Patrick. Most make at least an attempt at following a storyline, while some are actually quite good. Typically, they will feature 6-8 sex scenes with a variety of sexual situations (ie., straight sex, lesbians, vouyer, anal, etc.).

Lesbian Videos
Lesbian videos have become immensely popular and typically also feature the female superstars of porn. You'll find anything from girl-girl scenes to girl-girl-girl scenes to massive orgies of lesbian lust.

Compilation Videos
Compilation videos don't waste time with storylines or plot. They are simply a collection of back to back sex scenes. Some have limited commentary provided in between, but this is kept very short. Many compilations will follow a particular genre (ie. all black, all lesbian, all anal, etc.). You'll find 2 hour, 4 hour, 6 hour and even 8 hour compilations. These videos are usually lower cost than feature videos. Most of the time, the sex scenes are simply the scenes from older feature videos spliced together. They're good if you're not interested in a fancy storyline, or if you have a particluar interest in one genre.

Educational Videos
Educational videos seek to educate and inform the viewer regarding a variety of sexually related topics, from fellatio to sexual positions to general questions about sex. You won't find much hardcore action here, as educational videos tend to present their material in a classy fashion.

Gonzo Videos
Gonzo videos are shot as though the action is actually happening to the viewer. In these cases, the cameraman is also the lead actor and we see all that happens to him or her from their eye level.

Fetish Videos
As mentioned before, if there is a fetish for it, there is probably a video for it. Squirting, foot fetish, cum gargling, big boobs, small boobs, hairy, bald, bondage and almost anything you can imagine has been done before the camera and is available on video.