The feature is only available in Chicago, New York City, San Francisco Bay Area, Baltimore and Washington DC at the moment, but the company promises to roll it out nationwide over the coming months. Facebook has teamed up with various blood centers and organizations like the American Red Cross -- their requests for donations will show up on the social network's app and website, visible to users nearby who signed up to see them.

As Kate Fry, the chief executive officer at America's Blood Centers, said, it will help individuals "conveniently find and connect with their local blood center to help meet the ongoing need for a diverse pool of blood donors in the US and share their experiences and the importance of blood donation."

Those who want to help save lives can sign up by going to the new Blood Donations entry in the About section of their profile. They'll receive notifications whenever one of the partner organizations in their area publish a call for donations and will be able to view all the requests in the feature's tab.