March 20, 1998 was a bittersweet affair on the set of Babylon 5. It was the last day of shooting on the science-fiction television series and the final goodbye for the cast and crew. As actor Peter Jurasik (who plays Centauri Ambassador Londo Mollari) said in an online chat session a few days later, "It feels a little like getting to the end of a long race or marathon. There's a sense of, Wow, we did it. And we all did it together."

For once, the fans were included in that sense of camaraderie, as series creator and executive producer J. Michael Straczynski arranged for a computer terminal to be brought to the set so the cast and crew could chat with the fans in a daylong session. "Various cast members came by and chatted for a few moments here and there," Straczynski said. "There was someone manning the terminal at all times to give people a sense of what was happening on the set at that particular moment. It was sort of an online gathering of the family on the last day of shooting. That's never been done before to my knowledge."

It was a fitting farewell for a show that, at the same time it was revolutionizing science-fiction television, was forging a unique relationship with its fans over the Internet, creating what Straczynski calls a "worldwide community." The final episode of Babylon 5, Sleeping in Light, airs November 25. When it's over, Babylon 5 will be no more (although a sequel series, The Babylon Project: Crusade, is scheduled to begin airing on TNT early next year). And when it ends, so does Straczynski's grand online experiment.

When the pilot for Babylon 5 aired in February 1993, almost no one thought it would succeed. Many industry execs believed there was only room for one science-fiction series on television, a slot already filled by Paramount's behemoth franchise, Star Trek. But B5 didn't just survive, it thrived, eventually surpassing everyone's expectations. Straczynski conceived the series as a "novel for television" -- a pre-scripted, five-year-long story with a defined beginning, middle and end. Over those five years, Straczynski achieved the impossible: He showed there was an audience for science-fiction beyond Gene Roddenberry and proved it was possible to do lengthy, complex story arcs on American television.

In the process, Straczynski also aged a good ten years, sacrificed his sleep and spare time and wrote an astounding 92 out of 110 episodes (plus the pilot and four TV movies). Somehow, he also found the time to establish an unprecedented dialogue with his fans online.

"To my knowledge, no one has ever sat down and, day by day, week by week, for however many years it ran, chronicled the history of a television series online, talking to fans of the show so they could really understand it," Straczynski said. "Not only would it be, to my mind, a gesture of respect for science-fiction fans -- speaking as one myself -- who are generally told just to watch the show, buy the merchandise and shut up, but it would create a living document."

The thousands of messages Straczynski has exchanged with fans over the years (he spent, on average, two to four hours a day online) have all been archived online. (You can find them, among other places, on the Lurker's Guide to Babylon 5. The conversations included discussions of television's nuts-and-bolts, behind-the-scenes anecdotes, fans' personal reactions to episodes, sometimes harsh criticism, and, occasionally, obsessive lunacy.

Straczynski has had to deal with false rumors that he suffered a heart attack (which tied up the switchboard at his production company for hours), libelous comments about cast members, personal attacks, harassment, and, in one case, outright sabotage of his computer system -- factors he says contributed to his decision to end the ongoing dialogue.

"It does take a toll on you to deal with the trolls and the monsters and the manipulators," Straczynski said. "But secondarily, it is a very involved process, several hours a day, and my goal with this was to chart a show from conception to pilot to series to the end of the series. As Babylon 5 ends, so must this document. That doesn't mean that I will be gone entirely -- I'm too old and cranky to change my habits. I'll just listen more than I talk, which I think everyone will be relieved about, including myself."

Despite the aggravations, Straczynski thinks that going online can be a valuable experience for TV producers. "Television is so insular," he said. "When you're an executive producer, for the most part, everyone around you tells you yes. Whereas if you get online, you can get a response from Cleveland, Ohio saying, 'You suck, and here's why.' It tends to be very bracing, and it can make you consider what the hell it is you're doing.

"For me personally, it's been worth it," he adds. "And I think for the fans of the show, it's been worth it. There's been a great deal of struggle, angst and dead-catting going on for five years, but on balance, yeah, it was worth the effort." Chicago fan John Van Aken, who has been participating in the online dialogue since before the pilot aired, agrees with Straczynski. "I feel very privileged to have been here since the beginning," he said. "It's been like having a little window into the brain of the guy who created all this."

By any measure, Straczynski's television series has been a success. But has his accompanying online experiment been as successful? "It depends on how you define success," Straczynski said. "Do more people now understand how television is made and why things are done the way they are? I would say yes. Has it helped create a new community of people who have become friends and even gotten married because of the show? It definitely has. Has it cured cancer? Not that I'm aware of. But what we set out to achieve, I think we have achieved."