I had an idea! 
I originally said:
Then I saw
And I thought… hey, forget warnings and blocks … we could simply show, next to the new user’s display name, how much read time / posts seen in the current topic that new user has. Ambient info style! I had not considered this!
That’s not a warning, it’s just ambient information, ala the Steam example – how credible is a game review from someone who only played the game for 1 hour? 30 minutes?
Unfortunately it does nothing to prove the commenter actually read the source article, which is kind of a bummer, but you see where this is going. A new user who took the time to read most of the topic, versus drive-by new user who read almost nothing and began posting.
