Fast-growing small businesses are embracing social media like never before, according to recent data--and LinkedIn still dominates as the platform of choice.

The Center for Marketing Research at the University of Massachusetts Dartmouth released a new study that shows the big-picture trends in social media use among the Inc. 500--the fastest growing private companies in the United States-- in 2013.

Through observation and interviews with executives, researchers found that usage was up for nearly all social platforms--including LinkedIn, Facebook, Twitter, YouTube, and Pinterest--compared to the year before. (Foursquare was the only platform that saw a decline). And for the second year in a row, LinkedIn ranked as the most used platform, capturing 88 percent of those surveyed. Facebook is a close second, as 84 percent of small businesses are on the social network. 

Here are some other interesting highlights from the study: 

• Sixty-one percent of companies say that Twitter holds the most potential for sales growth. 

• However, approximately half believe that sales from Facebook, Twitter and Pinterest are less than 1 percent. 

• One in five companies have no social media plan in place. 

• About 40 percent executives said they have a strategy planned in case a negative attack occurs online. That's down from 54 percent last year. 

This is The Center's seventh annual study. When it first performed this research back in 2007, the study's authors noticed that Inc. 500 companies were outpacing Fortune 500 in their use of social media. Interestingly, this still appears to be the case today.

"The most recent data collected on both groups suggests that the pattern holds with 52 percent of the Inc. 500 blogging [compared to] 34 percent of the Fortune 500," the authors wrote.