Twitter was just officially granted a patent on the ubiquitous pull-to-refresh gesture — a touch interface concept the company acquired when it purchased Tweetie developer Atebits in 2010 and hired founder Loren Brichter, who invented the move.

"I had started working on the patent two months before the Twitter deal," said Brichter during a phone call yesterday. The application was officially filed the day before Brichter signed the Twitter acquisition paperwork. "The patent was the cherry on top," he says.

"I have plenty of feelings about the patent system and how broken it is."

But like many engineers, Brichter was worried about rampant abuse of patents in the tech industry, particularly software patents. "I have plenty of feelings about the patent system and how broken it is," he says. To alleviate those concerns, Twitter agreed to only use his patent defensively — the company wouldn't sue other companies that were using pull-to-refresh in apps unless those companies sued first. That's why Brichter had filed for the patent in the first place. "I realized that I'd invented something valuable and I could have a bullet in the chamber, god forbid."

That original defense-only provision developed over time into what Twitter is calling the Innovator's Patent Agreement— a contract between the company and its engineers promising that any patents developed during their employment will only be used defensively. Twitter rolled out a first public draft of the IPA just over a year ago, and after seeking feedback from a wide range of sources, the company is launching version 1.0 today alongside the pull-to-refresh patent. The agreement is wide-ranging and includes a provision allowing engineers to kill wrongful lawsuits by issuing licenses to their inventions if Twitter breaks its promises.

"The IPA is an expression of the values of the company."

And to keep everyone on notice, Twitter plans to include a copy of the IPA in all of its patent registrations — a formal reminder that the company is limited in how it can use them.

"[Engineers] were going around saying we're worried about what patents mean," said Twitter IP attorney Ben Lee, who drafted the IPA and guided it through the revision process. "The IPA is an expression of the values of the company."

Lee's work on the IPA began during his initial job interview with Twitter general counsel Alex Macgillivray in November of 2010. "The notion of trying to come up with new ways of handling patents was a major reason for me coming to Twitter in the first place," he said. "I don't think it was that long after that we were already having significant conversations with the engineers and senior management about some things we could do."

Unfortunately, work on the IPA was put on hold not long after Lee joined Twitter — a patent troll had sued the company over a junk patent on "virtual communities," and Lee spent serious time living in a Virginia hotel room as the case went to trial. "We've seen the negative impact" of patent abuse, he says. "And we're a young company."

"Guess his favorite beer."

After a year of work, a jury invalidated the troll's patent and Lee resumed drafting the IPA. He also began a process of outreach, confidentially soliciting feedback from people Lee calls "damn good lawyers" across academia and the legal community. Lee also had to talk to Twitter's management and board of directors — who were supportive even though the IPA meant Twitter could never build a lucrative licensing business like Microsoft's with the technology it developed. (It's hard to collect licensing fees when you've promised never to sue anyone, after all.)

"The board was very supportive," Lee said. "Anyone who's had significant exposure to patent issues in the Valley has very strong opinions on what the proper way out is." The next step was naming the agreement — and after a lengthy meeting with the engineers resulted in nothing, inspiration struck. "Alex will kill me," says Lee with a smile. "Guess his favorite beer."

"The problem is how to define defensive purposes."

But while promising to use patents only for defensive purposes makes perfect sense at first blush, it becomes much more complicated in practice. "The concept is easy to explain," says Lee. "The problem is how to define ‘defensive purposes.'"

Perhaps unsurprisingly, that definition in version 1.0 of the IPA is fairly broad: Twitter can still sue any company that files, threatens, or even voluntarily participates in a patent lawsuit against Twitter, its affiliates, customers, suppliers, or distributors. It can also sue any company that's filed or participated in an offensive patent lawsuit in the past 10 years, and it can further use IPA patents to "deter" a threatened patent suit against Twitter or its users, affiliates, customers, suppliers, or distributors.

That's a pretty wide open list of targets — Twitter can certainly sue Apple, which has filed several patent lawsuits against Android smartphone vendors in the past few years. It can also sue Google, whose Motorola subsidiary has sued Apple and Microsoft. Yahoo? Check. Microsoft? Check. (Twitter isn't planning to sue any of these companies, says Lee. "All of these companies are our partners," he says. "It's not something that has even come up.")

Twitter attorney Ben Lee, author of the Innovator's Patent Agreement

"There's a million good reasons that maybe you went offensive," says Lee. "But once you've done it, there has to be some ramification for it — in this case, for 10 years, you've come out of the IPA." But finding excuses to sue other companies wasn't the point, he adds. "We took the best hack we could to make certain that when we say ‘defensive' it made sense to us."

Lee accepts the criticism that this first draft of the IPA leaves loopholes in play. "I think it's perfectly legitimate for someone to say, ‘You know what, that balance is crappy, the line should have been over here, or here.'" But he's proud of the work Twitter's done to involve the engineers in the process, and to give them some voice in how their patents are used. "So many engineers are taught to just not even bother looking at the application — to just sign and pretend it doesn't exist. That's not good. They're not part of the process in a way where they can actually help the situation."

"If other people can't use pull-to-refresh, they can never build on top of it."

Not so for the IPA, he says. "I would hope the relationship between [Twitter] and the engineer is different. The engineer has checks and balances."

Brichter echoes the sentiment. "I really hope this becomes the de facto standard for hiring — engineers could demand this in their contracts." He notes that pull-to-refresh was built on top of Apple's rubber-band scrolling behavior, and says good ideas should inspire more good ideas. "If other people can't use pull-to-refresh, they can never build on top of it either." He says other developers shouldn't worry about using pull-to-refresh in their apps. "Twitter and I see eye-to-eye on the patent system."

"Where the patent system works is recognizing an engineer for doing something cool," says Lee. "The rest of this is about doing something to fix the other aspects."

But even the part that works can feel strange: Brichter sounds slightly sheepish when I ask him what it's like to know he'll forever be credited with inventing pull-to-refresh, a gesture that has become a central feature of modern touch interfaces. "I think it's really cool," he says.

"It is a little weird though."