There is a period, usually about age four, when children love playing with words, saying them for no reason and inventing rhymes and chants.

For example, my eye happens to fall upon the word 'button' right now, and I can picture a 4-year-old saying 'button-mutton-lutton-nutton!' as she plays.

This song, with its 'Bickety, backety, book' formula, seems calculated to appeal to children in the same way. I'm not surprised the song has endured, even if in a quiet way.