Nice piece on answering the “who said that?” question, by Corey Robin in The Chronicle.
The Wrongly Attributed Statement makes you realize what a battleground a quotation can be. On the one hand, men and women invoke the authority of the great and the good to lend a little heft to their favored sayings. On the other hand, pedants like me rely on the authority of a different great and good in order to take that heft away. They have their Web sites, I have mine (Quote Investigator, which is run by Garson O’Toole, the nom de plume of a Yale Ph.D., is the best; Fred Shapiro’s Yale Book of Quotations is the most comprehensive and reliable source in print, and it makes the most use of online resources.) The quotation is a struggle over expertise, pitting the seemingly tutored against the seemingly untutored but revealing how dependent we all are on the authority of people whom we think—or hope—know better.

I did quote duty a lot in my life, as a legislative & news researcher, and a library nerd in general. But I didn’t have a patch on my mother, who for many years answered press inquiries for the Library of Congress’ Information Office. There is something strangely compelling about getting to the bottom of a hard to pin down quote. You could start a site up for these slippery characters. Corey has a couple, and I would add “From each according to his ability to each according to his need,” attributed to lots of people, among them Marx, but seemingly going back to maybe The Bible.
Tipped by the reliable Library Link of the Day.