The numbers are daunting.

43 % of Americans have registered as organ donors. But less than 1% of deaths leave organs available for re-use. And in many cases, the people who make the decisions about organ donation [relatives or spouses, usually] may not be aware of their loved one's choice.

Enter Facebook. The giant social-networking site has begun allowing its users in the US and UK the option of stating their desire to donate their organs after death. Like other bits of information on the system, users can specify whether their organ donor status is public, available only to friends, or private.

Facebook has also added a link to state registries that keep names of organ donors on file [while most people sign up when they receive or renew their driver's license, around 2 % of donors sign up through registries]. Even though signing up via your license or a registry is a binding decision for adults who take the step, decision makers may not be aware of the choice.

In the first day of the option alone, more than 100,000 US Facebook users chose to make their donor status known, while 6,000 more users signed up on state registries. While the best way to let your wishes be known is to tell everyone who may need to make that decision how you feel, the new Facebook feature will help get that word out.