It's where they interpolate between known datapoints and in so doing, create a more-detailed-and-accurate-than-you-might-like image. And it will be an evil thing, whether the image so drawn is even accurate or not.

I shall leave it as an exercise for the student to determine exactly how this might be so, and to further demonstrate with valid examples how this might be so.

Carry on.

Have a closer look at most of the people all around you.

Now read what you just wrote, once again.

This actually worked at the small enterprise where I take care of things. A user managed to get their machine mucked up with a bunch of spyware and adware by clicking in a forwarded email. I cleaned the machine and then management called a meeting a day or two later. Had every one of the employees in attendance. I gave the standard presentation about email safety, as well as general internet safety. I sat down. The director stood up and informed everyone in the room that the next time a machine needed to be cleaned as a result of operator error, the bill for my services (not cheap) would be deducted from the relevant employee's next paycheck. A sheet of paper was then passed around, with the same directive written on it, and all employees were instructed to either sign or lose their job. They all signed.

That was two years ago. Have not had a SINGLE instance of any malware on any machine, since that time. People now ask me every time they have any doubts about what they're doing, and I've headed off a few potential catastrophes since that started happening.

I'm guessing it's not a coincidence.

Space Shuttle don't cause 'em, but it creates them. (how's that for logic?) Here's some pictures of the Shuttle's vapor trail in the high atmosphere, noctilucent. Pretty cool looking, eh? http://www.flickr.com/photos/35423990@N00/sets/72157600329483616/