the King Arthur Flour phenomenon

When I was in 8th grade, my school put on the musical Camelot. Shortly thereafter, the supermarket got a new brand of flour- called King Arthur flour! Or so I thought, until my mother told me that that flour had always been there- I just hadn't noticed it, because King Arthur had no special meaning to me. Since then, I've thought of that as the King Arthur Flour phenomenon: you learn a new word or idea, and suddenly it shows up EVERYWHERE. Kind of disconcerting- why did you learn it that time, when you didn't learn it all the other times you were exposed to it?