The problem: I recently gave in and joined Facebook. Nearly all of my friends, family, and co-workers were already avid users. Right away, I was flooded with emails from Facebook letting me know someone requested me as a friend, accepted my offer to be a friend, commented on my wall, or did anything connected to my account. I received hundreds of messages within the first 24 hours.
The solution: I created a folder (named “Facebook”) and a mail filter (supported by most email clients, including the Rackspace Webmail interface).
Now, when I get an email about my Facebook account it bypasses the inbox and goes straight to the "Facebook" folder. This saves me time because I can avoid investing time in emails that aren't urgent.
I filter email from co-workers into specific folders for the exact opposite reason. The filter allows me to deal with those emails first. If the boss emails me, it goes to a folder and I know to check that first. Setting up filters only takes a few minutes but saves me hours of wasted time manually sorting through messages.