THE MAN waited in line for at least 10 minutes before getting to the TICKETplace counter. "Do you have any tickets for the American Ballet Theatre tonight?" He asked. "Yes," he was told. "I don't want any," he said. "I just want to see what you have."

Dubious, curious -- he just wanted to know if TICKETplace was real. Some people think the seats on sale are just crummy ones, or that nothing will be available, or that the ticket they get is just a voucher that has to be turned in for the real ones at the theater -- all unture. It's just a question of getting used to TICKETplace.

Since TICKETplace opened Nov. 10, business has doubled. Aping its prototype TKTS in New York, albeit on one-sixth the scale, it sells half-price tickets the day of performance, hoping to corral along the way new, more venturesome audiences. If a person can't get a ticket for the attraction he sets out for, the reasoning goes, he might try another one (although a survey taken recently showed that most people got the ticket they came for). Full-price tickets are also sold for future dates.

TICKETplace is run as a nonprofit project of the Cultural Alliance, which commissioned a survey last year that found 1.1 million tickets went unsold in Washington every year. The idea was fairly simple: a central location where unsold tickets could be sold the day of performance for half-price. The goal is that by the start of its third year of operation it will be selling 10 percent of the 1.1 million, which may not seem like much, but nonetheless represents seats filled that would otherwise be empty, and money in tills that would otherwise not be there. The word thus far from box-office operations in town is: It's working.

It cost $180,000 to start up, about $90,000 for the construction and design of the booth and the rest for staff salaries and the computer operation. It will lose money this year, a shortfall Cultural Alliance director Peter Jablow will make up with grant money. It is intended to be self-supporting, however, living on the service charge on each ticket sold and billboard advertising on the booth.

It is not designed for comfort: You wait in line, sometimes as long as half an hour, outside, and unless you are intimately familiar with the seating plans of all the major houses, you won't have much idea, other than a general location, where your seats are.You must pay cash and you can't buy tickets over the telephone. The advantage is: $32.50 tickets for $16.25, or $8 tickets for $4 -- plus the service charge (50 per $10 face value). A service charge of $1 is added for full-price tickets.

Some statistics:

* The first week TICKETplace sold 693 tickets; the fifth week 1,386.

* In the first seven weeks, 7,635 tickets were sold, 4,932 of them theater tickets, 1,291 music and opera, and 1,412 of them dance. These numbers do not necessarily reflect the popularity of the discipline but rather the availability of tickets.

* In the first four weeks the Eisenhower Theater sold the most tickets -- 1,011 -- through TICKETplace, way ahead of the next total, 453 for the Washington Performing Arts Society.

* The most requested ticket is for "Evita," which was not on sale for the first two weeks. Box-office treasurer John Griffin expects business to pick up after the holidays and thus fewer tickets for TICKETplace.

* Most ticket buyers are between 25 and 40, well-educated, with an income starting at about $25,000 (this information culled from entrance and exit questionnaires). Most people decided to go within a week of the performance or the day of it. "It seems to be most appealing to young singles, and may eventually, as TKTS has done, become a better place for pickups than your local bistro," joked Jablow.

* Any organization that is a member of the Cultural Alliance can use TICKETplace; about 100 of the 250 members are performing arts groups and 28 of them used it in the first month. The only theaters that do not participate are the commercial ones: The Warner, and DAR-Constitution Hall.

So far Jablow wants to make only one change: to make people wait farther from the window so that the line will spill out onto the sidewalk. "When I see a long line it really gives me a thrill," he said. "All those people buying tickets."