NEW : Facebook says users in U.S. and U.K. can sign up . Comment: ` But I think that if people choose to share these stories with their friends , that can make a big difference over time . '' Mark Zuckerberg says the move may `` make a big difference over time '' More than 114,000 people in the U.S. are awaiting organ donations , government says .
NEW : Facebook says users in U.S. and U.K. can sign up . Comment: Mark Zuckerberg says the move may `` make a big difference over time '' More than 114,000 people in the U.S. are awaiting organ donations , government says .