You are not required to reply to each one individually, or even really at all. But you can make a status that's like "thanks for the birthday wishes!" or something. Also, it is annoying that mom messages me on facebook instead of emailling me now, too, but it is something I check a lot so it's much less annoying for me than for you.
(no subject)
Date: 2010-11-05 04:33 pm (UTC)Happy birthday, btw