Junk mail is not only annoying, but poses a huge threat to the environment. The US Environmental Protection Agency estimates that 44% of mail is disposed of without even being opened. It is also estimated that 100 million trees are cut down each year, and 28 billion gallons of water are used in production of junk mail in the US alone.
You can learn more about the environmental threats of junk mail here. If you want to stop receiving mail that you don't want, sign up for Catalog choice- a free service that allows you to opt out of mailing lists- here. Make a difference in the environment and in your daily life.