If you're old enough to remember the days when a VCR was an expensive novelty item that you or your parents occasionally rented from a video store (along with a couple of prerecorded movies to watch over the weekend), then you've lived through the biggest period of transformation the entertainment industry has undergone since commercial television caught on in the 1950s.

When people started buying their own VCRs about 20 years ago, things began to change in a bunch of really interesting ways. One effect was that you were freed from the tyranny of the TV schedule and could tape things for later, which somebody dubbed "time-shifting". That led to a side benefit (from the viewers' perspective) of being able to fast-forward through commercials and film credits and thus maximize your valuable viewing time. VCRs also granted new powers like being able to pause, replay, speed up, or slow down the action.

The public now had some degree of control over broadcast media and also, I believe, began to develop a sense of ownership or entitlement to the content. Except for the then-recent introduction of cablevision, TV had always been a free medium, and what "free" means to most people is, "whatever you can pick up is yours to keep." The full ramifications of that attitude didn't become clear until the Internet made it possible for people to share music and movies with each other internationally.

But that doesn't mean that people aren't willing to pay for programming. The best example is what happened with prerecorded movies: if the price was reasonable (say, about three to five times the cost of a rental), lots of people would buy films instead of heading off to the rental shop. Not everybody, but more than enough folks to make an impression. One culturally positive result of that was that the movie studios and copyright holders began to mine their storage vaults for more product to release, often going to the trouble of restoring old films or presenting themed collections. Some companies like Kino Video, Criterion, and Rhino even sprung up to concentrate specifically on obscure and cult releases.

Once the movie companies realized home video had joined theatrical release, foreign-distribution rights, and broadcast sales as a significant market, they began to pay more attention to consumer interests and desires. By the time DVD came along, that trend was well-entrenched. In effect, DVD combined the viewing quality and cinephile appeal of laser disk with the accessibility (and lower retail price) of VHS tape. In fact, a lot of content got cheaper once it hit DVD, in part because the manufacturing and shipping costs are lower. It's a pretty efficient format.

The latest result of all these converging vectors is the phenomenon of television shows collected and released on DVD. Admittedly, this also happened with VHS, but not often. Columbia House's mail-order clubs offered a few mainstream sitcoms, the BBC put out a few tapes of their better-known productions, and programs with a lot of viewer loyalty--like Star Trek and Monty Python's Flying Circus --were distributed, but that was about it.

But now things are almost getting silly. It seems like everything is coming out. Sometimes the shows in question are as rare or obscure as old foreign films, but in many cases they're programs you can see just by turning on your TV. And yet people pay for them. Sure, there are usually bonus features, cast interviews, and outtakes added onto the DVD releases, but that's obviously not the sole factor motivating people to take cash out of their pockets. For whatever reason, people want to own TV shows. There's even a Web site called TV Shows on DVD ( www.tvshowsondvd.com/ ) devoted not only to listing current and upcoming releases but also to lobbying for even more series to be made available.

So, the consumer is really beginning to drive the marketplace. Three recent examples come to mind. The strong DVD sales of the cancelled series Family Guy have prompted new episodes and a feature film to be commissioned. After more than 40,000 people signed an on-line petition promising to buy Freaks and Geeks if it were made available, it came out earlier this year. And finally, after an extensive (and expensive) process of music-rights clearances, the long-awaited packaging of SCTV episodes has finally begun. Some other shows (notably WKRP in Cincinnati and The Wonder Years ) are still hung up over music-rights issues, because the original producers never anticipated the retail-sales market developing the way it has.