It’s probably the same for everyone; the first thing you learn to read and write is your own name. This is a common practice in the circles of graffiti writers too. The graffiti spotter learns over time (if he is lucky) to decipher the writing, or at least to recognise from the style what he is looking at. But when suddenly everyone is writing the same name? That usually means it’s someone’s birthday and everyone congratulates by writing the corresponding name. The spotter is at a loss and capitulates. He knows he has to practise a lot more!