Apart from birthdays and events, you do not really use Facebook to communicate with your real friends; that, perhaps ironically, is what WhatsApp is for. No — the people you most enjoy stalking on Facebook are people you met in a hostel in Krakow five years ago on an Interrailing trip, or erstwhile friends from primary school whose lives have taken an unexpected turn — perhaps a turn that involves sharing close-up pictures of their body contorted, grotesquely, around a pole in a grey gym hall. This, you learn, is the move they’re taking “to nationals in May”.