Knowing your way around Google

Most of us feel like we have a pretty good grasp on how to search for topics easily in Google, but did you know that Google can do a lot more than simply search the web? It has quite a few tricks up it's sleeve, both trivial and useful. There was a list of 10 Google tricks on Digg.com, but the bandwidth overload had exploded the website. So someone in the comments posted a link to 7 Clever Google Tricks Worth Knowing. Even if you feel like you know all the calculator, define:, site:, and "phrase" tricks, I promise you there's something you don't know in this list -- maybe even something that will change the way you use Google.