Scenario: technical interview, question arises something regarding Unicode text in memory.
Interviewee: "hmmm, wish I could ask Joel Spolsky or at least remember his Unicode essay..." Interviewer (potential future manager): "Joe LaSpoli? Who?" Interviewee: "Joel Spolsky. You know, Joel on Software, co-founded Stack Overflow?" Interviewer: "Hmmm, cool, I'll have to check him out."
If interviewee is ultimately offered a job, is this a red flag or no big deal?
Not a flag, red, green or otherwise.
I'm not accusing you of doing this, but some people that are well versed in the cultural hacker scene constantly play out an obnoxious variation of this in the form of:
"You've never heard of X? Really? C'mon, X, the inventor of Y?"
It does not endear them to their colleagues.
I'm happy to talk about figures in computing with anyone else who shares a similar interest, but I make zero correlation of their competencies whether they know of a certain figure or not.