As a badge of pride or a piercing insult, "fanboy" is wielded too lightly. We must understand its history, its context, and its gravity! We must know its provenance! We must respect the (word) fanboy.
Harry McCracken has done some impressive forensics on every tech comment section's fallback insult. Evidently, it all started 37 years ago.
Try 1973–when a handful of copies of a fanzine were distributed at a Chicago comics convention. The zine was credited to two fans who took Marvel Comics, the work of Frank Frazetta, and other matters a wee bit too seriously, Alfred Judson and Bill Beasley. And its name was Fanboy.
A zine! Perfect. The self-applied insult had started as a mutation of "funboy," and came into existence to fill a void in language. What do you call an overly earnest middlebrow devotee? An exceedingly enthusiastic fan? A dweeby hobbyist? Without a word like fanboy, all our labels would be either clunky or offensive; imprecise or derogatory. In fanboy we have the perfect insult: soft, precise, and easily appropriated by its victims. It's versatile.