If you've done anything right in your brand management, you've probably managed to gather some fans. These fans think you (or your site, product, or brand) is the best thing since sliced bread. Have you noticed them? Have you really noticed them?
Here's a thought. Communicate with those fans. Pick a few of the ones that have the widest influence and give them an actual title. Promote them to "Official [brand] Evangelist". Give them a badge that they can proudly display on their site or social profiles. Your encouragement and official approval of their extreme fan-dom will prompt them to evangelize your brand even more. Now you have an official team of fans who are motivated by "title and recognition" to go out and build links and enthusiasm for your brand. The only cost to you is a little time to notice and communicate with your fans.