There are numerous reports in both newspapers and on the radio (I haven't had the TV on, but no doubt it is there too) of an American diplomat who supposedly said on Al Jazeera that the US has been "arrogant and stupid" in Iraq.
The only problem is that the diplomat was speaking in Arabic (good to hear that they can do that!) and Arabic can be tough to translate into English.
So do we think that every media outlet that passes this story on has had their own translator check the accuracy of the translation? Or is everyone just assuming that since someone ran the first story, and then someone else respectable ran the story, that it must be right?
In information cascades, you will frequently have everyone coming to the same wrong conclusion, even when their own private information suggests a different conclusion. The situation above could be a perfect example: a reporter who knows a little Arabic might check the actual words, but if they are not expert, then they will put more weight on the cascade of everyone else saying the original translation was right than on their own opinion. The result? A cascade of the same story, with the same translation.