With all the excitement at the moment about the NSA watching your internet traffic, I can't resist adding a bit of folklore from the early days of the internet.
Back in the good old days before web pages, the standard system of community chatter were newsgroups. In fact newsgroups still exist. The newsgroup for mystery novels for example is rec.arts.mystery.
There was a bug in the original newsgroup system, so that sometimes one or two lines from a posting might randomly disappear.
This instantly gave rise to the belief that a creature lived inside the internet, and that it survived by eating random lines of text. The creature was dubbed the Line Eater. People even added what was called Line Eater Food into their posts to make sure the creature had enough to eat.
I first became aware of the Line Eater in the mid-eighties (I'm showing my age here); the Line Eater lived for a few more years, until it was finally extinguished when someone found the bug. I'm stretching my memory, but I think it was that if a line was exactly 80 characters long and began with whitespace then the newsgroup software overwrote the buffer and simply dropped that line.
RIP the Line Eater.
The Line Eater inspired another theory: that the NSA was reading all the posts in every single newsgroup, and that the missing lines were the proof. This became known as the NSA Line Eater and was much more sinister. The anarchy-oriented denizens of the internet began adding what they called NSA Food to the signatures of all their posts. They added words like KGB, bomb, assassin, and, of course, NSA, all designed to tweak the interest of the eavesdroppers. This was all very silly, but since the early netizens were uni students, that's par for the course.
Except that as it turned out, the NSA really was reading all the posts. It was part of a massive traffic analysis system called ECHELON. Traffic analysis means keeping an eye on who's talking to whom without necessarily reading the messages. ECHELON was a Cold War construct run by the US, UK, Canada, Australia and New Zealand. I wouldn't be at all surprised if this Prism thingy turns out to be merely a subset of Echelon, which has been running for at least fifty years.