Is blogging dead? Not quite, but a recent survey of Inc. 500 companies reveals that it could be on its way out as a marketing tool. The study, conducted by the University of Massachusetts's Center for Marketing Research, included interviews with executives at 170 companies on the 2011 Inc. 500. Last year, only 37 percent of Inc. 500 companies maintained blogs, down from 50 percent the year before.

According to Nora Ganim Barnes, director of the Center for Marketing Research, it's not that these businesses stopped blogging; it's that they never blogged in the first place. "A lot of the Inc. 500 companies weren't in existence in the early blogging years," says Ganim Barnes. "They are newer companies that moved directly to Facebook and Twitter."

Still, the companies that do have blogs are very happy with them. Ninety-two percent of those businesses called the platform a success, up from 86 percent in 2010. Facebook, though more popular than ever among Inc. 500 companies, saw its success rating decrease 3 percentage points in 2011. Eighty-two percent of the companies that used Facebook deemed it a success.

"Blogging has gotten a bad rap for being too time-consuming," Ganim Barnes says, "but it's an invaluable tool to these companies. It's the only place where you can really be a thought leader in your field. You can't do that in 140 characters."

Companies that do have blogs are very happy with them. Ninety-two percent of those businesses called the platform a success.