Lars Rasmussen — one half of the dream team that led in the creation of Facebook’s new Graph Search and run its development — is leaving Menlo Park and setting up shop in Facebook’s office in London. Graph Search, or at least the engineering part that he oversees, is coming with him. I took the opportunity of a quick reconnaissance mission he made to the city this week to ask Rasmussen about why he’s coming to the UK, what is on the road map for Graph Search, internationally and otherwise, and what challenges lie ahead.

Graph Search has yet to launch in any other language other than English, and Facebook’s international user base is growing faster than its U.S. audience. But neither of these are the motivations for his move.

Rasmussen is coming for personal reasons: his girlfriend lives in Athens, and he’s tired of the commute from California to see her. So, because he has no intention of leaving Facebook, he’s decided to move as close as he can to Athens while continuing to work for the social network. And Graph Search, his baby, is coming with him.

How long does he intend to stay? “It’s a one-way ticket,” he told TechCrunch today. It’s also about coming full-circle. Years ago, Rasmussen studied for his PhD in Edinburgh, Scotland and only moved to California to follow his advisor when he migrated west. From there, Rasmussen ended up at Google, where he worked on Google Maps and Google Wave, before in 2010 leaving for Facebook.

For now, where Rasmussen goes, Graph Search engineering goes. So this week, he’s in town not only to find a place to live, but also to lay the groundwork to hire a new team of developers to work on Facebook’s new search efforts from here.

He says he’s put out an offer to the Menlo Park team for any of them to come join him in London. The rest will stay in California and keep working under Tom Stocky, the other Graph Search supremo. “So far no one has put their hand up high to move here but I’m pretty sure I’ve heard a hint or two that some folks are interested,” he said. Rasmussen is moving over permanently in August.

Third pillar, but a moveable one

For a product that Facebook CEO Mark Zuckerberg referred to as the company’s “third pillar” after News Feed and Timeline, Rasmussen’s move and what it will mean for Graph Search sound pretty freeform at the moment.

It’s not exactly clear what part of Graph Search’s development will end up with Rasmussen in London, and what will remain in Menlo Park, nor how the two teams will work together with thousands of miles between them. (Note: from personal experience, it’s possible.) It’s likely that all this will only get decided after they figure out what talent can be recruited — classic Facebook, as one person described it to me.

Rasmussen also says that he can’t say for sure whether Graph Search’s international push will definitely be a part of his work in London because taking it international will not be a quick task.

“When it comes to internationalizing graph search, we may do it here but we may do it elsewhere,” he said. “We’ll only do it when we feel the product is mature and makes sense. We’re still in the beta stages with a million or few million users. Graph Search is a long term investment we realize we have years of work ahead of us.”

He notes that although “internationalizing is the best path forward”, it will only come when the team has “hit the nail on the head with a good search product.”

“We are not talking weeks or a few months, though. It will take longer,” he added.

Natural language, and acqui-hires

One of the big things with Graph Search, as engineer Xiao Li and research scientist Maxime Boucher point out in an essay published yesterday, is that it is built on a natural language interface. But that will pose a challenge when Graph Search goes to other languages.

“I hope that the model that we started creating for English will work roughly speaking for all of our markets, but it’s not something that we have looked too deeply at,” he said. “Graph Search has a natual langauge component, so it will be an extra challenge to internationalize it. It was a challenge we expected because we want to have people ask natural questions, but we realize that it means that it would be a challenge to make new languages. That’s a reason for the long delay.” He added that even though a minority of Faceboook’s users speak English it’s still the single language in which Facebook has the most users.

While Facebook has been pretty good at internationalizing its products, doing so with a product like Graph Search, based on users inputting search commands in their own words, is unchartered territory. Rasmussen said that Facebook may end up having to buy their way into it, as others like Google and Yahoo have been doing.

“It’s possibly an area where we wil have to acquire,” he said. “It is something we’ve invested in in general, but we haven’t quite built the tools out for this thing. So possibly, if the right startup and talent came along, this is definitely something that we would consider. We’ve had some very successful acquisitions of small startups that have brought tremendous talent to the company.”

As for hiring in London, Rasmussen’s looking forward to it and how it could impact Graph Search. “I think there is obviously lots of Euroepan talent speaking different languages so it might come in handy, but again it’s not the primary reason. We are doing research on Graph Search here on par with what Menlo Park is doing.”

See the original post: Facebook’s Graph Search Supremo Lars Rasmussen On Relocating To London, Building A New Team, And The Challenges Of Natural Language