title: Storing data in Greasemonkey scripts
body: <p>Does GreaseMonkey have something built in so you can store data per-site or per-page?  For example, say you wanted to tweak StackOverflow.com so you can add a note to each of the questions in your favorites list and sort on that note.  Does GreaseMonkey have something built-in to store those notes?  Or perhaps can the scripts self-modify, such that you just define an array or object and keep the data there?</p>