I doubt if any television show in the history of the medium has inspiredmore traffic on the Internet than ``Mystery Science Theater 3000,'' the showthat elevates to an art form the ancient practice of talking during a movie. OnCompuServe, just in the past week, more than 800 messages have been posted. Ifyou add AOL and Prodigy and the Web and the Usenet, there must be thousands.

It's as if the sight and sound of all those ad libs inspires fans to log in withtheir own.

Now there is a movie to go along with the TV show--or, moreaccurately, to act as a rebuke to the Comedy Channel, which chose this very timeto announce that they are not renewing ``MST3K'' (as its fans call it). Although``MST3K'' will probably find a home elsewhere, its loss would be bearable ifonly because we can do at home what the stars of the show do on the tube, whichis to provide a running commentary on some of the worst movies ever made.

But perhaps you are not familiar with the show. I've described it toany number of people who told me they'd never heard of it, only to have themsay, ``Oh, yeah--that show with the funny silhouettes down at the bottom of thescreen. I always wondered what that was.'' Those who have never seen the showwill find it easy to get up to speed for the movie, which explains the wholepremise at the top. We learn about the diabolical Dr. Clayton Forrester, atwisted scientist who hopes to rule the world by frying our brains with theworst movies ever made. Will his plan work? To find out, he conducts experimentson the Satellite of Love, where the innocent Mike Nelson is his psychologicalsubject. Mike fights back against brainwashing by using his sense of humor--hewisecracks all through the horrible movies, and is flanked by his robot pals,who join in.

``MST3K'' looks easy enough that anyone could do it. But althoughwe can all shoot a basket, not all of us are Michael Jordan, and the key to theprogram is in the scripting. My guess is that the show's hypothetical audiencesconsist of brainy techno.nerds with a wide and eclectic familiarity with popculture, politics, literature and the movies. And to keep audiences on theirtoes, the program occasionally throws in esoteric references that may becompletely meaningless to all but a few viewers.

Part of the appeal of the program is in the wisecracking. But themovies themselves are also crucial. They are so incredibly bad (many of them arenot only out of copyright but perhaps were never worth copyrighting in the firstplace) that they get laughs twice--once because of what they are, and againbecause of what is said about them.

The odd thing about ``MST3K: The Movie'' is that its target is not thatbad--or at least, not all that bad. On second thought, maybe it is. Let's put itthis way: I liked it a lot more when I was 12 than I do now. The movie is ``ThisIsland Earth'' (1955), starring Jeff Morrow, Rex Reason and Faith Domergue. Itgot fairly good reviews 40 years ago, although today the props and makeup areludicrous, and whoever gave Morrow his towering forehead was seriouslyoverestimating the credulity of the audience. As the film opens, Reason is saved from a plane crash by amysterious and cheesy green ray, and soon receives a mysterious shipment ofstrange scientific parts, which he assembles with the assistance of a TV-likedevice that functions about as helpfully as the directions that come with mail-order bookshelves. The equipment allows him to contact an alien (Morrow), whoinvites him to dinner (much hilarious comment from Mike and the robots aboutgood manners in seeming not to notice that the aliens look weird). Soon thehumans board an airplane that looks from the outside like a DC-3, and from theinside like a plywood set. Mike boasts, ``I'm fully instrument rated forMicrosoft Flight Simulator!'' They fly to alien headquarters, where theydiscover only they can save the Earth from the evil plans of one of the alienfactions. ``This Island Earth'' was 87 minutes long, but ``MST3K: The Movie''is itself only 73 minutes long, and since it has scenes of its own, we only seeabout 55 minutes of the original movie. Nothing I saw made me want to see more.

The problem with attending a movie like this is that it makeseveryone into a comedian, and there's the temptation to wisecrack right alongwith Mike and his friends. Some people will find that alarming, since there'salready too much talking in movie theaters. My own feeling is that movies getpretty much the audiences they deserve: People tend to be quiet for good movies,and noisy during bad ones, and ``This Island Earth'' gets just about what it hascoming.