Tip for getting buyers to take that next step

I found a tweet by UpThemes that caught my eye. In a test on their website, they found that ~90% of purchasers will tweet or share a theme in order to get a $15 discount. You never know what will make someone pull the trigger, and this seems like a fun test, especially if you can compare it to overall conversion rates, and track those social share URLs to see what referred users do from the link.