They should do this every year
Hey Pig Monkey, We noticed that one month from today is the 4 year anniversary of when you first began hosting with us! Time flies, eh? As a thank you for your loyalty/patronage/what have you we have created a $20 DreamHost gift certificate for you! This email is it! You can use the gift certificate on your own account (greedy!) or you can send it to somebody else!
I switched to Dreamhost in April 2002.