The business-networking site provider LinkedIn on Tuesday launched an organizational directory service for groups such as professional organizations, alumni associations, and industry-conference organizers.

LinkedIn for Groups has been available as a free beta version for approximately one year, and counts more than 800 organizations as members. The premium version that debuted Tuesday brings additional services designed to attract exposure and new members to a participating organization. Two levels of the premium Groups services let an organization"s members display the official logo of the organization on their profile and allow the logo to display in search results.

"For alumni associations or industry conferences [LinkedIn for Groups] provides a way to advertise the organization through its members. Word of mouth is the strongest form of marketing," said Konstantin Guericke, cofounder and vice president of marketing at LinkedIn.

Another example of how LinkedIn for Groups can be used is to help technology conference organizers plan the event, send invitations, and keep in touch with attendees after the event"s conclusion.

Pricing for the premium versions of LinkedIn for Groups starts at US$5,000 for the first year. A free version of LinkedIn for Groups will still be available.

Current member companies of LinkedIn for Groups include CNet/Esther Dyson"s PC Forum and Delphi Group"s Business Process eXcellence industry conferences. The Association of International Product Marketing and Management and alumni associations from such schools as Caltech and University of California, Berkeley"s Haas School of Business are also members.

LinkedIn"s basic networking site has over 3.2 million users, most of which are professionals and executives who use the service to manage existing business relationships, according to Guericke.

Next month LinkedIn plans to launch another set of premium, paid services targeted at job recruiters and research analysts.