By day, Paul Guthrie is a physicist at the National Aeronautics and Space Administration. By night, he is Corwin, part of an electronic subculture populated by Daria Danae, Blacknight, Teen Rebel and other computer buffs who are revolutionizing the way people communicate with each other.

Thousands of computer users are hooking into national and local networks to flirt, joke, court and debate over what one enthusiast calls "the thinking person's CB radio."

There has even been one on-line wedding.

Members of the electronic network say another communications revolution--as significant as the invention of the telephone--is underway. But while the telephone made it unnecessary for people to see each other while they talk, the computer is making it unnecessary to even talk.

Some subscribers spend hours on the computer each night, accumulate bills of $100 and more a month, and consider their on-line friends--many of whom they have never met--as close to them as the people they see every day.

"It's like discovering a small club of very strange people," reports Guthrie, 34, of Hyattsville.

Users join the high-tech club by subscribing to national information "utilities" such as CompuServe and the Source, which generally charge $5 to $7.50 an hour at night to tap into the modern-day equivalent of a giant party line.

The utilities, which also offer electronic mail, on-line clubs on hobbies like gardening and photography, access to stock market information, airline schedules and other data bases, together have more than 100,000 subscribers. And their numbers are growing rapidly.

Locally, computer buffs on limited budgets can call up one of the 30 or so Washington-area bulletin boards, generally free, to sell a lawnmower, get help with the latest high-tech game, or to meet new friends.

Unlike the national utilities that allow users to talk back and forth simultaneously, the local bulletin boards work more like a speedy mail service. They are generally run by area computer clubs, software stores, or hobbyists.

Some are all-purpose boards, while others cater to a specific clientele such as teen-agers, gays and aspiring science-fiction writers. There's even a dating service that runs personal ads and allows people to send messages back and forth before actually meeting.

On the national level, one of the most popular ways to meet on-line is through electronic cocktail parties conducted over CompuServe's CB Simulator.

There, party-goers frequently use offbeat handles like their CB counterparts on the highways. Just like at a cocktail party, the conversation is disjointed, superficial chatter, often interrupted as people come and go.

During one recent evening, some of the messages coming across the screen:

"Feeling immoral tonight."

"Greetings, Corwin. Tell me about your handle."

"I'm looking for someone, sorry!"

Once initial contact is made, party-goers can move to a private channel for more in-depth conversation or a one-night stand. Some develop intimate, long-term relationships.

One Texas couple who met over the CB decided it was only fitting that they be married that way. After repeating their vows with the help of an on-line minister, George "Mike" Stickles and Debbie "Silver" Fuhrman delighted their guests with a lengthy (((((KISS))))).

Congratulatory messages from all over the country were flashed to them and all the festivities were covered by CB gossip columnist Cupcake.

"When I tell our friends you can do this on the computer, they're amazed," say Guthrie's wife, Anne, 34, director of the TechnoLit Center, a computer learning center in Washington.

The Guthries and other observers see telecomputing as the wave of the future.

Enthusiasts claim the computer is simply not the antisocial phenomenon critics have called it. Far from feeling isolated as they sit night after night at their individual computer terminals, participants say they have never had more friends or felt more connected.

"You are not alone with the machine," says Paul Guthrie, who uses his home computer about four nights a week--"but I sure as hell am not doing finances. A great revolution is brewing. Things are happening that have never been done before."

CB regular Daria Danae says the biggest problem she has is signing off the computer each night. She has made so many on-line friends that whenever she says she has to go, "someone else screams, 'I've got to talk to you!' "

Danae, otherwise known as Susan Rogers, a secretary at a Boston-area detective firm, says she tries to limit her computer time to one or two hours a night. But it's difficult, she admits.

She once was hooked into her electronic world for 9 1/2 straight hours, she confesses. Most of that time was spent in a long, private conversation with Super Scooper, a "close male friend from Texas" whom she has never met.

Rogers says it's nothing for her to spend $100 a month for computer time. Some months she has spent over $500.

Part of her popularity stems from the fact that she is a woman. The computer world is still largely male, so when a woman signs on, she generally gets a great deal of attention.

Monica Berry, who works in an Arlington "hi-tech" store by day, says men outnumber women by 15 to 1 on the free local dating network she runs through her bulletin board, The Best Little BBS (bulletin board system) in Arlington.

Berry, 32, who is currently dating someone she met through her service, says electronic dating is much better than the singles-bar scene, especially for shy people.

You find out about someone slowly, before arranging a live meeting. Daters already have at least one common interest--the computer--which can be an ice-breaker.

Berry says a number of people who met over her bulletin board are now dating, but whether anything more long-lasting will develop she doesn't know. Because the board has only been up since June, "There isn't a track record yet."

Although the electronic interaction lacks body language and face-to-face meetings, participants point out that it is also unencumbered by initial biases people might have toward someone because of such things as age or physical appearance. The anonymity also allows people to be less inhibited and to say things they might not otherwise.

Ray Daly, who runs two bulletin boards through the Program Store in Washington and Seven Corners, believes a different form of friendship is emerging over the computer, similar to when telephones became widespread.

"No one thought 100 years ago that you could stay friends with people across the continent over the telephone. But it's done all the time."

Says Rick Hosking, editorial director of Link-Up, a new magazine dealing exclusively with communications and the small computer, "We think it's going to be the biggest area in small computers. There has been a drop-off in home computer sales. That's because there is nothing to use them for. You might balance your checkbook a few times or plan a few meals."

Most households, claims Hosking, don't really need such a tool. But the capability of a home library or instant communication with people all around the world is a different story.

William Spencer, president of New Era Technologies, a Washington-based firm that sells communications software, is looking forward to the time when home-computer users have the sophisticated software--already available for large computer systems--that translates one language into another.

It "has the potential," he says, "to be the nervous system of our planet. It can enhance communication among people who otherwise would not have met."