Obama specifically mentioned the #NotInMyName campaign, launched by the London-based Active Change Foundation to condemn the Islamic State by saying their actions don't represent British Muslims. A number of Muslim leaders around the world have overtly condemned the Islamic State, too, from Sacramento to Germany.
#MuslimApologies represents another reaction: Frustration over the assumption of collective responsibility.
Muslims in the United States, for instance, face problematic public perceptions of their religion: 50 percent of Americans believe that Islam, more than other religions, encourages violence among its believers, according to the Pew Research Center.
The tweets include quips about inventions birthed during the height of Islamic civilization, forgiveness over the mechanics of ablutions, and sorrow for general phenomena such as Vanilla Ice.
Here are a few: