Careful readers of the New York Times may have noticed a change recently that could play havoc with historians for years. The newspaper of record is now dating its online articles with the date the pieces are posted. As most pieces are posted the day before they actually appear in the print edition, this means there will now be two publication dates: an online edition date and a print edition date. From now on historians citing the NYT will have to indicate carefully which edition they are referring to to avoid sending their readers (and fellow historians) on fruitless searches through the archives.

Conveniently the Times indicates at the bottom of every online piece the date of the print edition version. But inevitably some historians will cite the online date and others the print date, leading to confusion.

You've been warned.