It's actually quite touching, and I totally appreciate it. But also: a puzzle. How do you properly acknowledge all of this good will? Unless you have like four friends, answering each post is a losing proposition.
OPTION 1: THE BLANKET THANKS You see this one all the time. Thank you all for the birthday wishes. It really means a lot to me. There is nothing wrong with this approach. It's the easiest practical way to genuinely thank everyone for their thoughts. And frankly, it's your birthday; you shouldn't have to sit around all freaking day responding to facebook posts. You should be getting DRUNK. Because you're old now, and every year brings a new kind of pain. DROWN IT OUT WITH CHEESEBURGERS AND WHISKY.
OPTION 2: POST A PHOTO A nice compromise between the blanket thank you and something more personal, posting a photo is a great way to share what you're doing with all of your friends. You know, bring them into the celebration using the tools of the modern Internet. You can even hold up a sign with a personalised message. (See above.)
OPTION 3: DO NOT RESPOND Some say that publicly thanking everyone on facebook is just a covert attempt to lure in a few extra last-minute birthday wall posts. Not the most hopeful theory, but it might be true in some cases. But you wanna know something that's definitely true? Nobody really cares if you don't holla back at them for their birthday salutations. Think about it: Do you sit around refreshing your feed, waiting for a response every time you post a birthday wish? No. You finish your coffee, and put on some pants. Silence is a totally acceptable option.
OPTION 4: WRITE A POST ON A POPULAR WEBLOG AND DEDICATE IT TO YOUR FRIENDS Some would call this *abuse of power*, but the only person at Gizmodo with the authority to tell me what to do is presently on holidays. So I'm gonna do what I want. This post is for all my friends and family. I seriously love you guys, and don't know what I'd do without you.