yeardrop

or "yeardropping"

An action under the same category as namedropping - used to describe the case where a person uses any rare occasion to mention a specific year with the purpose of sounding a bit superior.

Generally used by douchebags or academic hipsters.

Bill: "Oh, remember to backup the computer before doing anything, right?"

Steve: "Don't mind that, I got TimeMachine - automatic backup since 1997"

Bill - (darn, I hate when he's yeardropping my ass)