Ticketmaster, trying to fight the computer tactics used by some of the most advanced ticket scalpers, has sued 21 people, accusing them of fraud and breach of copyright in circumventing the company's online security system to try to buy huge numbers of tickets.
In the lawsuit, filed last week at U.S. District Court in Los Angeles, Ticketmaster accused Joseph Shalom, a producer of live entertainment events in New York, as being the central figure in a coordinated series of attempts over the past two years to obtain large numbers of tickets and resell them at a profit.
According to the suit, Mr. Shalom and his accomplices used "bots," or specialized computer programs, to bypass online features like Captcha -- a series of distorted letters or numbers -- that test whether a potential ticket buyer is a human being.
Ticketmaster, a division of Live Nation Entertainment, says Mr. Shalom and others linked to him used these systems to gain access to as many as 200,000 tickets a day ahead of the public, aiming for the most desirable tickets.
Ticketmaster seeks unspecified damages in the suit and does not say how many tickets were actually purchased by the accused. But it also says that the use of bots damages Ticketmaster's reputation and harms the public.
As a result of the behavior outlined in the suit, the company says, "the inventory of tickets available to consumers who do not use such devices is substantially diminished, which has led some consumers to question Ticketmaster's ability to ensure a level playing field for the purchase of tickets."
Bots have become a major target for consumer and industry complaints over the ticketing market, as consumers grow frustrated by the now-common experience of concerts selling out moments after going on sale, then seeing listings for those tickets at inflated prices through online secondary markets like StubHub, owned by eBay, or TicketsNow, part of Live Nation.
The concert industry has been frustrated over how to crack down on bots.
Three years ago, federal authorities charged a group of men with using similar tactics, giving them $25 million in profit. But the men were sentenced to probation, which music executives say has not served as any deterrent. Concert promoters and other have said that the use of bots has become increasingly common, particularly for the most in-demand shows.
In a statement, Ticketmaster said: "We care about protecting fans and the integrity of our business. We are doing exactly what we have repeatedly said we do: Stand up for the fans who use our site in the proper manner."
Mr. Shalom did not respond to an email requesting comment.