... lots of beverage producer use additional to the design work on top of the bottle cap also the inside of the bottle cap to display information or grafics. The range goes from simple text messages over clip arts all the way till high solution pictures.
... several breweries used the inside print of their bottle caps to display bar games like stone / sissiors / paper or dice games to be played at home or in bars.
... a few years ago the first inside prints were used to display winning tickets to draw prices. The consumer realised after opening the bottle if he won a price or not and had to send the assembled bottle caps to the brewery to claim the price.
... newest developement ist, that breweries print inside the bottle cap a code to participate in a price drawing. The consumer has to register the code online and will receive message if he won a price or not per electronic message (email / text message) Lately there were even offerings to sell unregistered codes online.