LinkedIn likes to send you a lot of emails. On any given day, you might get 10 different emails blabbing on about birthdays, contacts joining or other annoying notices. To unsubscribe from all of them, it takes a bunch of clicks, but developer Chengyin Liu created a bookmarklet to unsubscribe in a click.
LinkedIn has a lot of dropdown boxes that you have to go through to unsubscribe, and it takes a little while to get through them all. The bookmarklet does it for you. Just grab the bookmarklet from Digital Inspiration below, drag it to your bookmarks bar, then head to LinkedIn's email settings page. Click the bookmarklet, and everything changes to "no email". You'd think the bookmarklet method would take too long to be worthwhile, but it's still somehow faster than LinkedIn's clunky method.