The Yahoo Query Language (YQL) has been around since October 2008, and since then received a lot of positive coverage from inside and outside of Yahoo. While there are a couple of obvious purposes for which YQL can be used, there are others that are a bit more subtle.
This article assumes that you already know what YQL is and how to use it. (If not, the YQL Guide is a great start). Instead we focus on the areas in which YQL shines, although the technology might not always have been meant to be used for these purposes.