ark Napier sold some of his art this month. For an artist whose digital works have been shown by the Whitney and the Guggenheim in New York, this should neither be significant nor surprising. But Mr. Napier's medium of the moment is the Internet, where the art that one sees is not a material object to collect. And with nary a guarantee that this kind of work will even survive the next power outage, sales of online art have been scarce indeed.

Yet Mr. Napier has succeeded in selling three $1,000 shares in "The Waiting Room," an interactive, animated painting that has been hung, so to speak, in a private corner of the Net. Although he created the software that drives the work, its sights and sounds are generated by the online actions of its owners. As they click on the screen, pastel-hued spirals, ovals and squares appear and begin to swirl against a black background. Each shape is linked to a sound file that yields an accompanying hum or chirp.

Mr. Napier hopes to sell as many as 50 shares in "The Waiting Room," an approach that emphasizes the work's participatory nature. When multiple owners view it online at the same time, they can produce shapes that complement — or obliterate — those made by others. The work is the visual equivalent of an Internet chat room with "conversations" occurring in geometric shapes instead of words.

"The piece is meant to be seen not as 50 copies but as a single artwork that is literally a shared space online," Mr. Napier, a 40-year-old New Yorker, said. "So when somebody possesses this artwork, they are really sharing it."

Mr. Napier's strategy is the latest attempt to find a workable model for selling online art. As interest in online art has increased, artists have been stymied in their efforts to get paid for digital creations. Museums have commissioned and, in a few cases, acquired such virtual works. Mostly, though, online pieces have been a labor of love.

Even if he sells all 50 shares, Mr. Napier said, "clearly, I'm not in it for the money." Not entirely, anyway. His motivation was to develop a viable economic model that would help sustain the nascent genre. He said: "If you can't get a support system going, then the art will fade. It needs an audience, and it needs some sort of pull coming from the other side."

Because of the nature of the medium, Internet artworks obviously resist being turned into commodities that can be bought and sold. The traditional art world economy is built on the notion of the rare object. With an online work, there is no tangible object to own. Nor can a piece that can be accessed from any computer in the world and copied perfectly be considered rare.

There are other issues. A work may no longer be viewable once the relentless push of technology renders obsolete the hardware or software on which it was designed to run. And as many publishers have learned, people are reluctant to pay for online content that has been available at no charge. A work, "p-Soup," similar to "The Waiting Room," is freely accessible on Mr. Napier's Web site, Potatoland.org.

Without income from their virtual works, some of the online art pioneers have returned to more conventional high-tech media. For instance, the New York artist John F. Simon Jr. makes wall displays for which the images are controlled by computer. "It's economics," he said. "I would love to spend time doing pieces online if I could pay the rent with it, but I have to work where I can support myself."

Has Mr. Napier cracked the code on how to sell online art? With three buyers in three weeks, it would be premature to say. Besides, there will be no real proof until a resale market develops for online art.

Mr. Napier's solution appears to be a savvy compromise between marketing art and marketing software. In the software business as in the music industry, a lot of copies of the same thing are sold at a relatively low price. Because "The Waiting Room" depends on its owners' actions, access to it must be controlled or it will become a visual jumble.

By offering no more than 50 shares, Mr. Napier has been able to make "The Waiting Room" into a limited-edition Internet site, which functions more like a live performance than a static artwork. The shareholders are buying a ticket to an event that they can attend anytime they wish. Although they also receive a certificate of authenticity and a CD-ROM that contains the software, these are like "Lion King" T-shirts. The work's value resides not in its keepsakes but in the experience it provides for the viewer.

This is not the first stab at selling online art. Some ingenious artists have tried to market their online projects, from complete Web sites to handcrafted computer viruses, by putting them on a collectible CD-ROM. Others have offered signed printouts of screens from their work, just as performance artists sell photographs and other memorabilia from their acts. But by converting these transient works into material commodities something gets lost in the translation.

Mr. Napier, who was trained as a painter, argues that "The Waiting Room" is every bit as tangible to him as works made in more traditional ways. He said: "Once you forget that there's a computer mediating this, it is just as physically there in the space as a canvas. It's just a question of shifting an art culture that for centuries has been immersed in the collectible object."

The shift, if it happens, will not be accomplished quickly. Online art is still an unfamiliar form. Steve Sacks, the owner of Bitforms, a new-media art gallery in Chelsea, which is selling "The Waiting Room," said some visitors have trouble grasping that the work is constantly changing and should not be frozen. He said: "People keep asking, `Can I print this?' Or they say: `I love this composition. I just want to stop it.' I say that's not what it's about. That sometimes turns people off."

The ephemeral quality of the work as well as its dependence on technology raises questions about its longevity. No one worries about the life span of a symphony or a play because there is a musical score or a script. For online art there is computer code. Mr. Napier said that when the time comes that he or an associate cannot maintain "The Waiting Room," its shareholders will get copies of the code. If necessary, they could hire someone to update the piece for the technology of that future time.

The first shareholders in "The Waiting Room" are undaunted by these concerns. Mark Addison, who teaches art history at the University of Colorado in Boulder, said: "A lot of art is ephemeral. I'm willing to accept that it won't last forever. If it does, and people are willing to rewrite the code, I'll go with that. And if not, we enjoyed it while it was here."