WASHINGTON, DC — The United States Patent and Trademark Office has rejected a group of 20 patent claims put forward by a Japanese holding company that sought to enforce a four-year-old patent on subdomains.Subdomains are exactly what the word implies: subdivisions of a larger URL, like “News.CNET.com.” The patent covers the concept and hints at implementation paradigms.

In 2007, Hoshiko bought the patent, originally registered by Ideaflood in late 2004. Although Ideaflood began enforcing its patent rights almost immediately — suing Google in October 2004 and About.com in 2005 (the Google case was dismissed and About.com settled within months) — Hoshiko ratcheted up enforcement action. Since the buyout, LiveJournal, FreeHomePage.com, T35 Hosting and others have found themselves on the receiving end of “pay up or else” threats from Hoshiko.

Consequently, the Electronic Frontier Foundation and others asked for a re-evaluation of the subdomain patent, claiming the practice existed long before Ideaflood applied for the patent in 1999. In fact, the methods the patent mentions for implementing subdomains have been integral aspects of the open-source Apache Web server since 1998.

After a review, the USPTO agreed, ruling the idea “too obvious to patent.”

Hoshiko has until March 15 to request a reversal of the ruling, but it must narrow its patent claims in order to encourage the USPTO to revisit the issue.

The EFF said the decision was a hopeful sign that what it considers dubious patents can be toppled.

“It’s an incremental process of change in the world of patents,” Michael Kwun, a senior staff attorney for EFF, told CNET.

His optimism further is bolstered by Senate Judiciary Committee Chairman Patrick Leahy’s recent announcement that patent reform is his top priority for this legislative session.