From the guy who wrote the book on Word of Mouth Marketing—literally—Andy Sernovitz—comes some great tips you can use to turn a thank you into great word of mouth marketing.
Never offer a normal thank you.
Only send gifts that make people say “wow.” No one wants to receive a gift basket full of weird food that you don’t want to eat. Try this: Flamingo Surprise will cover a lawn with 100 pink flamingos or happy faces. Ship the best BBQ from Tennessee. Send a cheesecake from the Carnegie Deli for less than you’d spend on a boring gift basket.
The Lesson: If you’re going to send a gift, make sure it’s worth talking about.
More Info: http://www.damniwish.com/2008/06/701-the-how-to.html