I came across a classic April fools' hoax (thanks Dorea):
In a nut shell - 2 radio hosts of a local Florida country radio station told listeners that DIHYDROGEN MONOXIDE is in their water system.
Lets spell it out DI - HYDROGEN = 2 hydrogens, and MONO - OXIDE = 1 oxygen, so the chemical formula would be H2O. Looks familiar? Of course, this is plain old WATER.
Now, it is not my intent to ridicule the majority of the population who are not chemical-savvy, and would rightfully say : "if people expect 'water' and don't expect 'dihysrogen monoxide' they would naturally be caught off guard and would expect the worst. This is the whole point of media bullets - to alert people"
And this is why the prank works so well. Relying on human nature of habit - knowing that news bullets alert us of an issue of importance, but also, if we are used to a certain terminology, anything new will confuse us.
Just imagine how people would react if news will alert people of highly-luminescent radiation-emitting resistive device which can cause sever burning and damage your eye sight if looked directly at?
People would start wondering what it is and how can we avoid it! Would they understand it means 'light bulbs'? maybe, maybe not.
Back to the H2O story, though, it is interesting to note that this prank is by far not a new one. Apparently, it is more than 20 years old http://urbanlegends.about.com/library/bl_ban_dhmo.htm
And even more amazing is that there is a website dedicated to the idea, called http://dhmo.org/ listing all the bad stuff water can cause (all of which is true, by the way - for example, it is the main component of acid rain!)
The moral lesson of the story is that we should always exercise critical thinking about what we hear in the media, however scientific it may sound. I don't mean you should never believe anyone, since when we are unfamiliar with a field of study, we have to rely on the specialists for knowledge. But we should always remember that facts can be presented in many ways, leading you to different conclusions.
Science is about examining the world as objectively as possible (and believe me, there are many stories of scientists who failed to do just that, on which I will probably elaborate in the future...), but as soon as we take a few facts, and make a decision on how to present them (order, choice of words, etc.) they become subjective.