Good question, Anonymous! We post throwbacks on weekends. They help pad out the queue so that we can post longer. Plus, older posts still deserve some lovin’.
EDIT: Oh man, someone just pointed out that I didn’t really answer your question! I’m so sorry! Throwbacks are in reverse chronological order. Basically, I started at the beginning of the archive and am working my way forward. In general, I try to space out characters and movies so there is as much diversity as possible, but I don’t think about it too much.