Mark Zuckerberg wants you to donate your organs.
Conversations over the dinner table with his medical student girlfriend convinced the Facebook founder that he could be doing more to help increase the supply of donated organs. Speaking to ABC News, Zuckerberg said :
Facebook is really about communicating and telling stories… We think that people can really help spread awareness of organ donation and that they want to participate in this to their friends. And that can be a big part of helping solve the crisis that’s out there.
The actual change on Facebook's part is small. Starting today, users in the UK and US can go to their timeline, click on "Life Event," select "Health and Wellness," and add the new option "choose Organ Donor":
Whether or not the initiative actually helps increase the number of organ donors remains to be seen. The ability to add it to one's timeline is fairly well hidden, and the act of signing up to be an organ donor isn't quite the sort of life event that Zuckerberg seems to hope. I joined the register the first time I got a Boots clubcard – not quite something I feel strongly about marking into the story of my life.
While it may make more sense to add as a binary category rather than a "life event" – so that it's alongside things like relationship status, religion and political views rather than births, marriages and deaths – the actual efficacy will depend on the rather capricious whim of the social network. If everyone who is an organ donor adds that fact to their profile, then those who aren't may start being aware of it in a way that may cause them to act.
There are a lot of "mays" and "ifs" in that, of course. It's equally possible that no one will update their organ donor status, and the initiative will go unseen. But if Zuckerberg succeeds, it will be one of the largest applications of "nudge theory " to date. The idea is that changes in the framing of a question – from highlighting the way peers answer to changing the default response – can massively change the proportionate outcomes. The most effective example of this is given by Sara Kliff at the Washington Post:
Organ donation rates are 25 to 30 percent higher in presumed consent countries, according to a 2005 paper  in the Journal of Health Economics. When Belgium instituted a presumed consent law in 1985, the number of organ donors nearly doubled  within two years.
Facebook is unlikely to get that sort of takeup. But if they manage even a tenth of the effect of presumed consent, that would result in around 400 extra donors a year in the UK and US, and around three-and-a-half thousand lives saved. Few can argue with that.