LinkedIn Corp. on Monday plans to launch a new recommendations service that will allow the social network’s more than 80 million members to post reviews of products and services linked to their professional profiles.

Participation is free and voluntary for companies, which would need to set up company profile pages and add products to be reviewed before users could leave a recommendation. The program has some 30 participating companies at launch, including JetBlue, Liberty Mutual Insurance, Microsoft Corp. and Harvard Business School Executive Education.

Participating companies will be able to review the recommendations, respond to them and possibly delete frivolous ones, LinkedIn said.

The closely held company has in recent months been adding new functionality  to become a hub for the information professionals need to do their jobs. “A big part of what we’re working to do is becoming the essential source of information for our membership,” said LinkedIn Chief Executive Officer Jeff Weiner.

Weiner said posting recommendations for products — alongside reviews for current and former co-workers — will help members build out their personal professional identities. For the companies, the service offers a “way to showcase their products and services and generate virality at scale,” he said.

The new program will also help build out LinkedIn’s marketing business, which provides about a third of the company’s revenue. Companies that allow their products to be reviewed will also be able to include a notice in their ads on the site that a product has been recommended by somebody in a user’s professional network.