You might be using Gmail every day, but it's possible that you're only using it for basic email sending and receiving, the embedded Gtalk chat, or occasionally using the search function. In addition to adding features through plugins that aren't originally available, Gmail itself has some functions that you may not have discovered or use rarely. These can't be called Gmail secrets, but rather eight things about Gmail you might not know. Some of these functions are interesting, while others are quite useful.