Professional networking service LinkedIn announced today that they’ll open a London office. Chief Executive Dan Nye explained the strategic move in a statement:“LinkedIn has seen outstanding growth in Europe in the past year, and by opening an office in London we expect to accelerate our momentum and better serve our users in the European market,” LinkedIn wants to double the number of members, which is now 18 million.

According to Nye, LinkedIn should grow faster in Europe. They have more than five million members now, mostly in Britain, Denmark and the Netherlands.

“I think in 2008 people will start to see the difference between social networking and professional networking.” And professional networking is different in Europe, Nye says. “In the U.S., people do business over the phone, through email. It’s perfectly normal never to meet someone you’ve done business with. In Europe, that’s really unusual. It’s much more of a personal interaction that people want to have.”

However, Europeans, – and especially the Dutch – seem to like professional networking tools. It’s remarkable that one of the smallest countries is responsible for a large share of the LinkedIn European user base. We earlier reported that Plaxo is also extremely popular in the Netherlands.

There is still a huge number of people who have never heard of LinkedIn and Nye wants to target them as well and he has a ‘healthy’ budget for marketing. So far, LinkedIn’s promotion was merely through word-of-mouth, a pretty good buzz and its networking effect . Now it’s time for the not so geeky crowd to start networking.