A funny thing happened on the way to having 500 television channels. All of the channels started to look alike.

Having more channels was supposed to lead to niche broadcasting, and for a while it did.

The Sci-Fi Channel, for instance, started out with a narrowly focused line-up of sci-fi and sci-fact programming, most of it reruns of 10- and 20-year-old sci-fi series like "Buck Rogers in the 25th Century" and "Battlestar Galactica."

That was 10 years ago. Now, Sci-Fi's programming is mostly horror movies and films that barely qualify as fantasy, like "Field of Dreams." Last November, Sci-Fi screened Mel Gibson's epic "Braveheart," which I don't think anyone has ever mistaken for science fiction, fantasy or horror, although some have mistaken it for history.

Recently, Sci-Fi canceled one of its best sci-fi programs, "Farscape," while picking up "The Dream Team," a show where ordinary people talk about their dreams.

As they say, it wasn't supposed to be this way. Futurist George Gilder wrote in his book "Life After Television" that broadcasting was dead and that "narrowcasting" was the future. And he seemed to make sense.

Narrowcasting allows the advertisers who pay for the programs we watch to target ads to particular viewers, making the ads more cost effective. It should be possible for a narrowcast channel to shrink its audience and still improve its bottom line. Meanwhile, viewers benefit by getting programs better tailored to their tastes.

But the programming executives who run channels like Sci-Fi aren't content to remain niche players, and it isn't the bottom line that drives them as much as it is the old way of thinking, which says more is better.

It's not about money as much as it is prestige.

As a result, it has become increasingly difficult to find sci-fi on the Sci-Fi Channel.

But you can find it elsewhere.

When it started, The Nashville Network catered to a narrow audience that liked country music, pro wrestling, tractor pulls and professional bass fishing. But "The New TNN," as it bills itself, is indistinguishable from other broadcast-oriented cable channels like TBS and USA. Reruns of "Star Trek: The Next Generation" anchor TNN's new prime-time line-up. And during the day you can catch episodes of "Miami Vice" and "Baywatch," if you like.

Then there is TechTV.

TechTV began as a channel devoted to technology news and reviews, a video version of Wired magazine. But in recent months, it has added science fiction to its schedule, starting with "Max Headroom" and following with Gerry Anderson's "supermarionation" adventure series "Thunderbirds."

This month, TechTV began airing anime during the wee hours, further upsetting its core audience of tech-heads, but gaining the channel new viewers.

Today, MTV has almost nothing to do with music, and Court TV airs police dramas to make up for the fact that nobody is much interested in watching coverage of trials not involving O.J. Simpson. Even ESPN is showing movies. About all you can say for narrowcasting is that at least Cartoon Network still shows cartoons.

If narrowcasting survives, it may be in the form of video-on-demand. ADV Films, for example, is experimenting with an anime-only, video-on-demand channel, which is currently available only to some cable subscribers in Philadelphia.

In the meantime, sci-fi fans will have to put up with "our channel" becoming someone else's channel. And so on.