I'm still a little confused on how the whole process works. What and how determines whether or not a question gets migrated, and where it goes?
When you vote to close a question as Off Topic, you are given the choice of voting to migrate it to another site. THe options availiable vary by SE site, and are determined by Mods/Admins. In the case of Arqade, the only availiable migration path of this sort is to Meta. If more than 3 close votes suggest migration to the same place, the question is migrated.
Additionally, Moderators can migrate a question to any other Stack Exchange site. This is not done often, and ideally, only after consulting with the mods or community of the destination site, to avoid rejected migrations.