By May Wong
The Associated Press

SAN JOSE, Calif. - A small company called Acacia Research Corp. went after some of the biggest names in broadcasting last month, suing nine companies for an estimated $100 million for allegedly violating its patent on streaming video.

That earned Acacia a spot on what the Electronic Frontier Foundation considers a top 10 list of intellectual property ignominy: patents the online civil liberties group is seeking to strike down as unwarranted and harmful to innovation.

"Good luck," said Paul Ryan, Acacia's chief executive. "Their chances are pretty remote."

Part fighting words. Part truth.

Only 614 of the nearly 7 million existing patents have been revoked, according to the U.S. Patent and Trademark Office. Some 3,927 patents have been narrowed since the agency began conducting re-examinations in 1981.

The hardest part for challengers is qualifying for a re-exam at all.

A challenger must find written evidence, called "prior art" in patent parlance, showing others developed the technology before the patent application was filed - a formidable task that consumes a cottage industry of patent researchers and lawyers.

One-time startup BountyQuest set out in 2000 on such a quest. It wanted to debunk questionable patents by letting interested parties offer rewards of $10,000 or more for hard-to-find prior art. But there were few takers and the business failed.

The EFF is similarly relying on volunteers - but without offering rewards. That's a surefire recipe for limited success, said Bradley Wright, a patent lawyer with Banner & Witcoff Ltd. "There are not a lot of people willing to spend free time to research for prior art."

Even when prior art is presented, re-exams are rare. The patent office held only 6,136 between the time the agency was authorized to do so in July 1981 and the end of March 2004.

The Acacia patent the EFF objects to is on "the transmission of digital content via the Internet, cable, satellite and other means." Another patent on its list, owned by Clear Channel Communications Inc., covers the distribution of digital recordings right after concerts.

"These companies are trying to claim a monopoly on the tools of free expression," said Jason Schultz, staff attorney at the foundation.

The group's list, chosen from 200 suggestions solicited through its Web site, focuses on patents it contends are being unfairly used to demand licensing fees from rivals or individuals.

Acacia and Clear Channel defend their patents and their right to seek royalties for intellectual property they say they spent millions to develop or buy.

Clear Channel bought the so-called Instant Live patent two months ago. It plans to charge an "extremely small" licensing fee - $1 per event in some cases - to artists who want to distribute freshly minted CDs after their concerts.