Hmm, I think for now it's relatively easily distinguishable. I've noticed that HN'ers feel "like me". So I look for that specific signal. I look for signals that care about curiosity and an insane hunger for the truth. Also, it's tough to mimic "Oh yea, I was at Xerox Parc programming this language that was posted about, let me give some nuanced insights into what was stated in the article" (that quote was made up for the sake of example).

The only marketeer that would be able to consistently fool me might be a marketeer that was a developer. But last time I applied for a junior marketeer position I was asked: given your resume, don't you want to be a developer instead? So devs seem to get pidgeonholed into always being devs.