You already tell Facebook your sexual preferences and your relationship status. You tell it your favorite movies, books, and music. You let Facebook know when you're happy, or sad. Facebook finds out when you just had a really great BLT. You make sure Facebook knows where you are, and who you're with. At this point, Facebook probably has a better conception of your identity than you do. Now Facebook wants to know what your post-death plans are for the contents of that fleshy sack of meat you call your "self." That's right, now, "you can add that you're an organ donor to your timeline, and share your story about when, where or why you decided to become a donor."
Honestly, it's a noble thing. Organ donation is important. It saves lives. According to the figures provided by Zuckerberg's press-release-cum-ABC-News-article, eighteen people will die today from lack of organ donation. And that really sucks, so frankly, anything that can increase organ donation is a good idea. So the fact that the new feature proclaims that "if you're not already registered with your state or national registry and want to be, you'll find a link to the official donor registry there as well," is a good thing, considering the Facebook user population is larger than that of any country in the world except India and China.
While the intent (raising awareness) is admirable, there's always the possibility that this will just become another way to humblebrag your compassion. Like a LiveStrong bracelet, or a "this is not a plastic bag" reusable shopping bag, putting the organ donor badge on your timeline might just turn into a way to prove you're a good person, instead of just, you know, being a good person. But I suppose the ends justify the means: the database will grow, and only good can come of that. So… I'm ambivalent? I just don't know anymore.
Personally, I'm excited for the inevitable glut of guys using the organ-donor badge as a way to pick up women. I predict late-night drunk Facebook chats will see a rise in the phrase, "I'll donate my organ! To you! Specifically, to your vagina! With said organ being my penis organ! Right now! What's your apartment number? I'm not drunk! Come on! Hey, did you sign off? What's your sister's number again?"