"These people all read Hacker News.
But they don't know that. Yet."
I parsed this as "each of these people don't know that he or she reads--as in will read--Hacker News." It sounded like an endorsement for Hacker News, rather than explaining that these people don't know that the people around them also read HN.
"These people all read Hacker News. But they don't know that. Yet."
I parsed this as "each of these people don't know that he or she reads--as in will read--Hacker News." It sounded like an endorsement for Hacker News, rather than explaining that these people don't know that the people around them also read HN.