SAN JOSE, Calif. -- Although you'd never know by gazing up at it, inside the Xerox Palo Alto Research Center (PARC) is an enormous mansion with hundreds of rooms, a place where scores of people from dozens of countries drop by each day for conversations, television-watching and an occasional food fight.
That this mansion exists only in a computer -- and can therefore be visited only from other computers -- apparently does little to diminish the pleasure experienced by its guests, most of whom are sitting in university computing centers connected to the global Internet network.
And the utter intangibility of "LambdaMoo," as the mansion is called, is of similarly little perturbation to Pavel Curtis, the Xerox PARC researcher who oversees it as a kind of computer-age lord of the manor.
LambdaMoo is an example of a "virtual community," a new and increasingly popular kind of computer program that's a combination of communications software and PC-style adventure game. By one estimate, there are 200 such programs in operation, including several on commercial networks such as CompuServe and Prodigy.
Some of these virtual communities are elaborate fantasy worlds that award points for epic feats such as slaying dragons. Others have an educational bent, for example, creating a science museum that high school students can "visit."
Still others, such as LambdaMoo, simply allow for rambling exploration with no particular agenda, making being logged on the high-tech equivalent of strolling through the neighborhood. There are familiar "places" to visit where, more often than not, friends from earlier sessions will be hanging out eager to chat.
For researchers such as Mr. Curtis, these programs are not just amusing diversions that captivate participants for hours, but sources of insight into the ways human beings interact with each other and the ways they may one day interact with computers.
The goings-on at LambdaMoo now are being studied by an anthropologist. And the same software that keeps LambdaMoo in operation is being reworked by Mr. Curtis to provide the world's astronomers with their own private computerized meeting "space." It also may soon do the same for researchers at the Xerox facility itself.
"People find themselves needing to be in touch with other people all over the world," Mr. Curtis said. "These virtual (P communities can play a part in enhancing that communication and improving the ways we can meet people at a distance."
This being the computer world, virtual communities answer to a number of acronyms, such as MUSE, for "multiuser simulated environment," or MUD, for "multiuser dimension." Mr. Curtis said the name "LambdaMoo" is his own, mostly whimsical, invention.
With a few exceptions, these programs don't draw pictures, but instead print descriptions on the screen of where the player is, who else is around, and what they are saying.
A typical LambdaMoo description runs: "This is a wooden deck behind the main house, facing southward across the pool to the lush gardens beyond. At the east end of the deck is a large hot tub. How Californian."
Unlike the older PC adventure games such as "Adventure" and "Zork," which allowed only one player at a time, many participants can be logged on to these newer programs simultaneously; at its busiest, 40 or 50 people are wandering through LambdaMoo's various rooms at once.
They can talk to each other -- and do, with abandon. Watching LambdaMoo in action is like watching a real-time transcript of a CB radio channel, with participants gabbing about whatever is on their mind, from school work to the day's news.
In those sorts of conversations, participants tend to act as they do in the real world, or conversely, as they wish they were able to.
For example, it has been noted that on these heavily male systems, a female who's logging on for the first time is more likely to receive offers of help than is a male.
Clearly, imagination is an important traveling companion in virtual communities. LambdaMoo-ers are able to have a "food fight," which actually means seeing something like this:
"You take the yellow rice pudding. The yellow rice pudding sails toward Abraxas, splattering all over. Haakon laughs. The spinach with lentils sails toward Abraxas. Abraxas ducks. The spinach lands with a splat."
Mr. Curtis acknowledged that while much of LambdaMoo is intentionally frivolous, the program makes an important point about the way people use computers -- that the more real-world knowledge people can bring with them in using a computer, the more successful they are going to be.
Just as the Macintosh and DOS Windows computers rely on a desktop metaphor, so can a software environment be constructed around "houses" and "rooms" that correspond to the real world, with each "room" created with a specific task in mind.
In LambdaMoo's chess room, for example, participants can draw a chessboard on their screen. In the virtual community being planned for astronomers, there will be a "viewing room" where pictures are stored and a "conference room" where people can go to see who else is logged on in order to have conversations with them.
And a Xerox PARC virtual community program likely will have a layout that matches that of the actual building. So if someone wants to know who is in or out, they need only go to the "reception area," where that information is normally available in real life.
Even people who initially dismiss the notion of computerized rooms as silly playacting eventually warm to the idea, Mr. Curtis said -- even if they don't go in the hot tub.
Anyone who has a computer on Internet can log onto LambdaMoo using whatever protocols they ordinarily use to make Internet connections. The host is "lambda.parc.xerox.com" and the port is 8888.