The Symbolic Global Allegiance of Terror Groups Like Boko Haram to Daesh

Following the emergence of Daesh, also known as ISIL, over the years, Emir Abu Bakr al-Baghdadi once called for jihadist groups around the world to pledge their allegiance. Dozens of militant sub-factions have done just that. But what does it mean, if anything more than symbolic gestures motivated by ever-changing dynamics on the ground?