There is only one word to describe this site, and it is “awesome.” XD
MyStickies lets you put little yellow post-it notes all over the Internet! Okay, so I haven’t really found a practical use for this yet besides “it’s fun.” Still, I suppose that if you needed to make notes to yourself about the content of a certain page, this is one way to do it.
Another, of course, is to use del.icio.us, which is a “social bookmarking system,” or just a fancy phrase “something which lets you see what other people think is worth your time.” I’ve found some very cool sites (including the one above!) this way, although the popular sites tend to be a little heavy on the IT nerd-type things.