From the site:
"The usual in honor of bookmark day will run until April 5th. Anyone can enter (who is over the age of 13) Please follow when you enter if you don't already...but it is NOT a requirement, I would just love you to return.
So what can you win...let's see....AN EREADER or GC of your choice from the bookstore of your choice....ereader type can not be more than $200 and GC is the same. All you have to do it fill out the form, follow(hopefully) and sit back and wait for the results...there will be extra entries given on Bookmark Day on the 15th of March!"