I hope to write a lot in this site about the online adult dvd market, how it has changed over the years, how it has affected other online industries, maybe try and get some employment statistics, although i have found that doing this sometimes tends to be unreliable, and the figures are never published, and so there is no way of verifying the statistics/figures.
There is no doubt that the adult dvd market has evolved, previous to being online, (before the internet) everything was offline, generally the prices were much higher (because of less competition) and there was much less choice for the consumer, as well as higher distribution costs and higher profit margins.
The online porn market as a whole has expanded enormously as more people - both companies and consumers have found that the internet is the perfect medium for the distribution of both porn and adult videos.