Last summer I was in Graz, Austria with the Ateneo Glee Club, at that time it was spring. During our walking tour of the city we passed by this store with blank colored papers taped to the store’s windows… on the paper people-passers-by would write stuff… messages, X heart Y, Z was here… etc. It  was a simple marketing gimmick that made people stop take a look at what was written or leave a message and look through the window into the store and it was interactive.