Despite the fact that social media has been a major component of recent editions of the annual South By Southwest gathering in Austin, Texas, social software company Expion found that sponsors of SXSW 2013 did next to nothing to maximize their marketing opportunities on Facebook.

According to Expion, General MotorsChevrolet was the only brand that focused all of its Facebook efforts on SXSW during the period of March 8 to 12, with 11 of the top 100 posts in terms of fan actions (total likes, comments, and shares).

Expion also found that energy-drink maker Monster Energy had the top eight posts on the list, but none were SXSW-related.

American Express, Miller Lite, and Pepsi were at the opposite end of the spectrum, accounting for a total of just 12 posts on the list.

Readers: Are you surprised that SXSW 2013 sponsors didn’t make more of an effort on Facebook?