The BBFC introduced the film certification system in 1912 to rate films for safety and protect audiences. Over time, the ratings were modified to better classify content for different age groups, starting with a universal rating and adding categories like adult, horror, A, AA, X, 15, 18, 12A. The ratings aim to isolate audiences by age but can limit profits by restricting who can view certain films. Other countries like Hong Kong also have film rating systems that vary in implementation and categories from the UK ratings.