Megan McArdle, the Atlantic:
http://m.theatlantic.com/national/archive/2011/05/out-of-osamas-death-a-fake-quotation-is-born/238220/Shortly after I posted my piece on feeling curiously un-thrilled about Bin Laden's death, the following quote came across my twitter feed: "I mourn the loss of thousands of precious lives, but I will not rejoice in the death of one, not even an enemy." - Martin Luther King, Jr
I admire the sentiment. But something about it just strikes me as off, like that great Marx quote about the housing bubble that didn't appear anywhere in Das Kapital. Owners of capital will stimulate the working class to buy more and more of expensive goods, houses and technology, pushing them to take more and more expensive credits, until their debt becomes unbearable. The unpaid debt will lead to bankruptcy of banks, which will have to be nationalised, and the State will have to take the road which will eventually lead to communism. Karl Marx, Das Kapital, 1867
Like the Marx quote, it's a bit too a propos. What "thousands" would King have been talking about? In which enemy's death was he supposed to be rejoicing?
A quick Google search turns up lots of tweets, all of them from today. Searching Martin Luther King Jr. quote pages for the word "enemy" does not turn up this quote, only things that probably wouldn't go over nearly so well, like "Love is the only force capable of transforming an enemy to a friend." I'm pretty sure that this quote, too, is fake.
...
Another fake quote I see a lot is the definition of insanity that keeps being falsely attributed to Einstein.