Lookups spiked on January 28, 2014.
In his State of the Union Address, President Obama celebrated the American Dream by pointing out that "the son of a barkeep is speaker of the House."
The prepared text of the speech read "son of a barkeeper," but, as James Fallows wrote in The Atlantic, "What Obama actually said about John Boehner was 'the son of a barkeep.' A tiny difference that was ineffably charming. Boehner himself was manifestly charmed."
Barkeep's charm probably comes from its slightly old-fashioned sound. We suspect that users looked it up to confirm that it is indeed a synonym of the more commonly used bartender.