The web is a messy place ... and errors are bound to happen. Consequently, you've probably run across your share of “Page not found” notifications.
This is what a typical old error page looks like:
The 404 page now shows a list of reasons, based on theories you once crammed to pass that Econ elective, why you haven’t found a page. Ideas include the Efficient Market Hypothesis (If you had paid enough for the page, it would have appeared), the Speculative Bubble (the page never actually existed and was fundamentally impossible, but everyone bought into it in a frenzy and it’s all now ending in tears), and Socialism (If you were to get the page you wanted you might get a better page than someone else, which would be unfair. This way at least everyone gets the same.)