Once you send Stackie or Ash your info, they'll send that info to another Secret Santa participant. So, let's say I was tapped to be your Secret Santa; I'd get an email that says "Guilty by Design's chinchillas would like hanging chew toys." Then I would make or buy that gift, and have it sent to your address anonymously. Once you get your gift, you'd have to try to figure out who your Secret Santa is based on the clues about me you'd be sent. My understanding is that you can enter your chins, your hedgie, and even the dog and the hamster if you'd like, but the catch is that for as many pets as you enter, you do the same number of gifts going out. So, lets say I still lived in my old place and entered the chins, the dog, and the snakes. I'd have to send out 3 gifts total as a Secret Santa, and I'd get 1 gift per entry from 3 different people.
Make sense?