"The broadcasting of one's presence contributes to the phenomenon of 'fear of missing out', or fomo. This is the idea that someone else is living a better, more exciting, life than you are. It's accelerated by the impression that comes from viewing other people's digital personas. The desire to broadcast one's presence may produce envy in others, but that doesn't mean that is the intention of the person doing it. The broadcast of self can express the sheer joy that comes from experiencing live music, even if it temporarily takes away from that experience. The phone is a way to have a friend who could not be present have a little slice of the experience. The 'wish you were here' isn't solely showing off – it's also reaching out."
Reason #5 (of ten) why "it's OK to use your mobile at a gig". Needless to say, none of them convinced me of anything other than the fact that author Wendy Fonarow must be using her platform on the Guardian site to troll.
(Thanks to Dave for the link.)