All this provides ­opportunity for job seekers on LinkedIn. But it also presents risks if LinkedIn profiles are not up to par.

One of the biggest mistakes people make is treating a LinkedIn profile as a quasi-personal site, recruiters say. People occasionally put up overly casual photos of themselves taken at parties or other nonwork venues, suggesting they are either not professionally mature or don’t take their profile seriously enough. Some people also link to news articles, videos, or other sites that might be seen as inappropriate professionally.

“LinkedIn is a site for professionals,” Fellers said. “It’s not Facebook, which is more personal. I’m not saying you can’t have fun and show creativity, but you have to remember who your audience is. You have to identify with the industry you’re working in.”

Another common mistake is not updating profiles to reflect new employers, promotions, or responsibilities in their careers, recruiters say. Too many don’t include photos or detailed lists of specific job skills. The latter is especially key if employers and recruiters are conducting word searches to identify candidates for positions, career specialists said.