Extra Features

Here's a confession: I'm one of those cavemen who still don't possess a DVD player. Don't worry, I plan to remedy this soon.
But what I still don't understand about DVDs is the apparent attractiveness of all these extra features. True, some, like the documentary 'The Battle for Brazil' accompanying Terry Gilliam's masterpiece, or 'The Making of The Shining' by Kubrick's daughter, really add to the movie you buy.
But who wants to hear audio commentary from Peter Jackson about how he had to do this shot 17 times because the orcs' tails kept falling off? There is such a thing as overobsessing about a movie (and if you plan to comment on this posting to point out that orcs don't have tails, then yes, you are overobsessing).
Anyway, this made me think. Do porn movies on DVD also have these extra features? And what the hell do the cast and crew say at the audio commentary? And which poor schmuck has to translate 'Ooh.. right there.. harder!' into subtitles in 29 languages?