LinkedIn is building up its European operations in order to carve out a larger piece of the social-networking pie here.

The professionals-focused social-networking site is stretching outside the US, building its targeted advertising program as well as selling its recently launched product for job recruiters, said Kevin Eyres, LinkedIn's managing director for Europe.

LinkedIn is playing a bit of catch up. It recently secured the domain after a dispute, just hired an advertising sales head for its London office and only offers the site in English, although plans call for more languages eventually.

LinkedIn trails in the number of users compared to other social-networking services. It has 20 million worldwide, although 1.3 million are joining per month, Eyres said. MySpace has 200 million registered users and Facebook has at least 70 million.

But what LinkedIn lacks in user numbers it makes up for in an important statistic for advertisers: The site's users are largely professional, their average age is 41 and their average income is $110,000, said Eyres, who spoke on the sidelines of Internet World, a web marketing and technology show going on this week in London.

Advertisers are willing to pay more for display ads on LinkedIn than other social networks. LinkedIn's "cost-per-thousand" - which is how much a company pays for its ad to be shown 1,000 times, known as CPM - is around $75 in the US and £25 in the UK. Other LinkedIn officials say those rates are far higher than what MySpace and others can charge now.

LinkedIn is combining its users' profiles and parsing information to offer advertisers carefully filtered target audiences. Advertisers can choose their audience by profession or industry and other profile information. LinkedIn users can block the scanning if they choose.

"The more levels of targeting, the more expensive it gets," Eyres said.

LinkedIn is also making a push with Recruiter, a collaborative human resources system, which was launched in February, Eyres said. Recruiters can hunt through profiles of users who have opted-in to allow searches. Several recruiters working for the same agency can have shared access to the system while they're sorting through candidates.

In Europe, LinkedIn's sales team is calling on HR departments to push Recruiter. The system is already being used in the Netherlands and the Czech Republic despite it only being available so far in English, Eyres said. Pricing ranges from $5,000 to $7,000 per user per year.