How does the sign-up form work?Signing up involves giving a little information about yourself, such as your name and email address, so we can send you information about your pairing. You can also use the sign-up form to tell us which characters and gifts you would like to send and receive. This information will be used to determine which people to match you with.
How are people paired?The actual assignment is a mystery until the final person has signed up. At that point, giver-receiver compatibility scores are calculated between each giver-receiver pair of people using the preferences participants’ reported on the sign-up form. Using these compatibility scores, we find the optimal solution that does not violate any constraints (e.g., someone being their own Secret Odin).
…Okay, but how are people actually paired?
You've awakened my inner math nerd. Here are the gory details.