With any form of social media your organization uses I think it would be a great idea to post short "Thank You" videos aimed to your supporters. This way they see who, and what, they are contributing to. It also makes for a more personal and special interaction between organizations. It could also be possible when using something like Facebook or Foursquare to give your supporters a better experience at your event by giving specials/rewards for "checking in" at your venue. This could be in the form of upgraded house seats(they already purchased their original seats), or other free gifts with the first person to "check in" to the performance. These can provide incentives for people to regularly use your social media platforms.