Jeff Weiner, a former Yahoo executive vice president, will become "interim president," handling day-to-day activities and overseeing all company executives.

Nye, a former executive at Proctor & Gamble, raised $80 million in financing for LinkedIn from Goldman Sachs and others. Weiner was an "executive-in-residence" at Greylock Partners, which has invested in LinkedIn, and at Accel Partners.

32 Million Profiles

The Mountain View, Calif.-based LinkedIn told news media that the transition was not hostile and is part of an effort to move the company forward. The site has 32 million member profiles, but reportedly few members actually use the site frequently.

LinkedIn faces an environment in which social-networking sites are looking to become more attractive to business users. In addition, networks of related social sites have been forming where users only need to sign in once to reference personal data like friends lists.

Leading the charge to connect social-networking sites are Facebook and Google, which have competing platforms. Various social sites are lining up with one or the other.

LinkedIn recently allowed third-party applications from Amazon and Google into its site, and Hoffman has said the company is working on letting its members use their LinkedIn identities on other sites.

Some observers point out that the poor economy could lead to greater use of LinkedIn by members looking for work or new opportunities.

'Ratify Your Value'

Brad Shimmin, an analyst with industry research firm Current Analysis, said he would have expected business-oriented social-networking sites, such as LinkedIn or Plaxo, "to have distinguished themselves more from, say, Facebook."

The emphasis at those business sites, he added, has been on providing controls for who you contact, which helps to "ratify your value as a business user," but this doesn't drive participation in the sites. The business-oriented sites, he said, are not really being used so much for networking as for providing a kind of "visible, public resume."

Shimmin said he expects Facebook, MySpace and similar sites, which have high levels of user participation, to be more successful as they extend into supporting business users, especially since the users, who tend to be younger than LinkedIn's, are accustomed to mingling social and business activities.

He suggested that LinkedIn and others could have more success if they offered compelling social-networking tools, as well as possibly offering private-label versions for enterprises.