LONDON — "He lived a hero, he died a martyr. . .if they killed one Osama, a thousand others will be born," says a comment on a Facebook group called "We are all Osama bin Laden." The group formed one hour after U.S. President Barack Obama's announcement of the al-Qaida leader's death. The group already has around 30,000 "likes." Moreover, there are more than 50 similar groups on Facebook.