[zarathustreal]

Why would Wikipedia be an exception?

[yesco]

Wikipedia offers it's external links via citations

[fuzztester]

And I guessed a while ago that this is why people on HN sometimes say "citation needed", when someone makes a claim about something.

[chuckadams]

To me it’s a snide passive-aggressive way of saying “bullshit”, and I can’t help but hear it in the Simpsons Comic Book Guy’s voice.

[gertlex]

Probably an exception in the "reason" for clicking hyperlinks, is what came to mind.

Of course another reply notes the clear external vs. internal link approach of wikipedia, too.