The concept of viral meme is not a mainstream academic concept and only merits the briefest mention in an encyclopedia  Meme is already treading on thin ground but is at least well known enough to be semirespectable  Lets roll isnt a concept at allits a phrase that has made the news recently and its the title of a song both of which deserve to be covered  Move zig is another phrase probably meaning more or less the same thing but it isnt worthy of inclusion here  It isnt even a common enough idiom to be found in a dictionaryyou certainly wouldnt find it say in a New York Times used without reference to its source  LDC