Bloomberg: When General Motors Co., the third-largest advertiser in the U.S., said it would pull ads from Facebook, it sparked a discussion about the effectiveness of marketing and advertising on social media sites. Here is what a handful of companies that manage brands on social media had to say:

Effectiveness Is Measured Differently

Adaptly, which handles social ads for PepsiCo Inc. and Kraft Foods Inc., said the ads and brand pages are for developing relationships and a network, which means that companies can’t measure them alongside the clicks and views they get on other sites.

                                                   

“Technically the ads are ineffective if you represent effectiveness in a traditional way,” said Nikhil Sethi, the chief executive officer of the New York-based company. “The whole notion of display advertising is real estate. Buy space on my website where people see it. And now there’s this whole model where the content has to be interesting in order for people to see it.”