TiVo made headlines last year for suing Verizon and AT&T for patent infringement over time-shifting DVR technology. Now Verizon is fighting back — with help from former Microsoft CTO Nathan Myhrvold's firm. In a counterclaim (PDF, 24 pages) filed Feb. 24 in U.S. District Court in Texas, Verizon alleges that TiVo is infringing on a patent that Verizon has licensed from Intellectual Ventures, Myhrvold's invention house and patent aggregation firm in Bellevue.

Intellectual Ventures, which has amassed some 30,000 patents, is viewed by some in the technology industry as a giant patent troll that extracts license payments from companies without actually producing anything. Myhrvold says his firm has not filed patent lawsuits — the classic troll strategy — and instead talks about his business in terms of "invention capital."

But Intellectual Ventures is showing that it isn't averse to helping other companies, like Verizon, in patent litigation.

The Intellectual Ventures patent cited by Verizon in the counterclaim against TiVo (U.S. Patent No. 5,410,344) is titled “Apparatus and Method of Selecting Video Programs Based on Viewers’ Preferences.” Verizon says TiVo "has been infringing and continues to infringe on the patent."

Don Merino, senior vice president of licensing at Intellectual Ventures, said he closed the licensing deal with Verizon on that particular patent in the last 72 hours. He described Verizon as an investor in Intellectual Ventures as well as a customer of the firm — and said he was pleased to help the company.

"This is a simple case of our valued customer had an issue," Merino said. "I worked with the people there to come up with the solution. If someone is beating my customer with a stick, we try to buy the stick from them. Or if we can't do that, we try to give (the customer) a stick that they can use to beat back with."

Verizon spokesman Bob Varettoni had no comment on the counterclaim or the Intellectual Ventures patent.

Merino said the Verizon deal is the first time Intellectual Ventures has licensed a patent to help another company defend itself in the midst of litigation. But he said he doesn't expect it to be the last.

"We expect to be doing a lot more of these in the future. We see this as one of our core potential values. No one else in the world has aggregated 30,000 patents," Merino said. He added: "For the right price, everything is potentially available."

Intellectual Ventures sold off a handful of patents recently to companies called WebVention LLC and InMotion Imagery Technologies LLC. Dow Jones, which originally reported the sales, noted that the two companies are "incorporated in Marshall, Texas, a favored venue for litigious patent-holding companies known as patent trolls."

Merino said Intellectual Ventures has done more than ten "divestiture" deals since last April, and described it as a pruning out of patents that have limited value or those that are only tangentially related to the firm's work. "It makes sense to turn over inventory periodically."

"We have a fiduciary responsibility to our investors to maximize the value of our assets over the broad portfolio," Merino said, adding, "At the end of the day we want to put these in people's hands who want to make some money."

Separately, Microsoft in January waded into TiVo's suit against AT&T, which uses Microsoft's Internet Protocol TV technology, dubbed Mediaroom, to power its U-Verse system. Microsoft is seeking to counter TiVo's claims against AT&T by alleging that TiVo violates two of the Redmond company's patents.

Previously: Myhrvold disputes 'troll' claim, makes case for 'invention capital.'