Article by Beth J. Harpaz
"NEW YORK—In Michigan, you're expected to leave snowy boots in the mudroom before going inside. In Alaska, boots are taken off in "Arctic entries." In Japan, Thailand and many other countries, you wouldn't dream of entering a home with your shoes on, regardless of the season.
But removing shoes before coming inside has not been the norm in much of the U.S.
These days, however, city dwellers and suburbanites from New York to Los Angeles often find that hosts expect footwear to be left at the door. Sometimes it's because of weather; other times, homeowners want to protect light-colored rugs and high-gloss wood floors from dirt and dings, or parents don't want street germs on floors where kids play."