It seems to me that Jimmy John’s–more so than other sub chains–has their Social Media Marketing game face on.
The brand is on Twitter, YouTube and Facebook and they have a frequently updated blog called FreakFast, where they’re busy directly engaging with fans via “Picture of the Day” uploads and other means.
Clearly, Social Media Marketing is easier to do when a company is already promotional and experiential by nature, as Jimmy John’s is. Take a look at how easy it is to translate those attributes to video: