There's probably a lot of people that don't "get" Gmail and delete all of their messages. There's probably also a lot of people who sign up for an account and d

There's probably a lot of people that don't "get" Gmail and delete all of their messages. There's probably also a lot of people who sign up for an account and don't use it, ever, and they contribute to the numbers. Keep in mind ~80 MB is for everyone on the planet (all nearly 7 billion) in 500 PB. I'm betting the average is a lot lower than we'd think.