"When you're looking for business service providers, in addition to just finding someone on the Internet that looks like they have a nice page, you also look for recommendations," said Konstantin Guericke, LinkedIn's co-founder and vice president of marketing. "In this kind of category, you're not just looking for any recommendations, you're looking for recommendations from people you know and trust."

For the new service, LinkedIn intends to draw on its existing network of business professionals for referrals and reviews. On the LinkedIn network, members form online "connections" with colleagues, co-workers, and businesses associates -- similar to social networks such as Friendster. Service providers with listings in LinkedIn Services are reviewed by LinkedIn's members; when members search for providers, the search engine returns businesses with recommendations from the member's connections first, followed by businesses recommended by the connections twice removed from the member, and so on. The reviews, which are not anonymous, can be posted only by registered members of LinkedIn.

The businesses in LinkedIn's directory are organized into eight main categories: legal services, financial services, employment services, creative services, management consulting, technology services, marketing services, and architectural and construction services.

Guericke said that 150,000 service providers have registered and created listings with the search service. The listings are free as of now, but Guericke said that LinkedIn will start charging soon -- likely after about six months. The model could be based on a Yellow Pages-type arrangement, where companies pay for more extensive listings, and thus appear in more searches, or possibly on a per-lead basis.

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