Article stolen from Shii's ... vanished wiki. Notice that the modern web & websites such as Facebook and those with Like buttons, Google login pages, etc are all tracking you and trying to take away your right to vanish / right to privacy (aka, the right to be AnonyMous).
If the Internet exhausts your patience, if you think you've said everything you need to say, if you screw up and don't want to bother covering your tail anymore... one day, you might need to just get the hell out of there. And when you do, you won't want anyone coming after you.
In case you ever need to do it, here are some tips for how to keep it your right.
You can also vanish in real life but it is much more difficult. For details, watch the movie Ghost World.