Josh James (co-founder of Omniture and current Founder of Domo) has done a great job of creating scarcity. Last I heard his product at Domo was still in “invite only” mode. He has hundreds of customers and markets a lot, but he maintains the “invite only” status for his business. By doing this he creates scarcity. He makes his current customers feel cool, and helps people not using his product to want it even more. If you’ve ever been in a relationship you have probably seen the scarcity principle at work!