This is a great tactic to use if you see plugins or themes that other people are using on their website, and you want to know what it is! Often, all you need to do is email somebody, but that can take days, or they may just think it's email/comment spam. This way you can take matters into your own hands!

Once you get a bit familiar with the code or know what you're looking for, you can see other stuff about their website too!