Sending birthday wishes on Facebook wall has become an action that you can't afford miss. Otherwise, your friend might be offended.. You can do this by posting a wish on your friend's wall on the friend's birthday. If you are not online every day or especially busy, you can use "Post Me Later " Facebook app. This app presents your Facebook friends ordered by their next upcoming birthday and allow you to write a personal message to each one. The message will be posted on your friend's wall on his birthday at the time you chosen. This is great for being the first to wish happy birthday to your love ones. For the lazy of us..."Post Me Later " also allow you to send a general message to multiply friends.