Facebook does it with its Sponsored Stories and other ad formats, why not LinkedIn? So must the business-oriented social network thought when it introduced in-house ads that used members' photos. Confronted with a backlash, the site says the ads will no longer display people’s photographs. LinkedIn, it would appear, crossed an invisible line with its users who expect more professionalism from the site than its more free-for-all counterparts, such as Facebook.

Journalists Use It

For example, LinkedIn is the most popular social network among business journalists, with 92% having a LinkedIn account, according to the  Arketi Web Watch Media Survey.

It is Very Important to Consumers Too

Also, consumers tend to place more importance on a LinkedIn account, according to a study from ROI Research and Performics, which found that 59% of online consumers rate having a LinkedIn account 4 or 5 on a five-point importance scale, compared to 53% giving this level of importance to having a Facebook account.

The Lure of Sponsored Stories

It is understandable why LinkedIn might have been tempted to tinker with its professional-like aura. Facebook’s Sponsored Stories is doing well for the site, according to VP of Advertising and Global Operations David Fischer. He recently told Fast Company that the unit was performing twice as well as standard Facebook ads - while still costing the same. "The key reasons it works is that it is engaging, it is social, and it is reflective of what brings people to Facebook overall, which is to share and connect," he said.