What commentators observed is the fact that there was no official protocol for announcing the royal baby’s name. So, Kate and William made things simpler.
George was the name expected for the baby in the last two weeks, even in the gambling world where many people placed bets. It seems that the middle name Alexander was selected because the name Alexandra was expected to be used for a girl. As the name Louis, probably this was chosen to commemorate Lord Louis Mountbatten, assassinated by Irish terrorists in 1979.
The new born royal baby has his own Wikipedia page, created sometime ago in the last weeks. He is the first person having a prenatal entry into this popular website.