That thread was started before the Polish module went to beta. So I guess I have a lot to learn about Duolingo in general, like where do I go looking for all this explanatory material that seems to exist outside of the comments attached to individual exercises. In other words, how was I supposed to find that thread?
well you can go to the discussion and then type "wiem znam difference" into the search
Why doesn't "I never knew about this" work. Is it because of the fact i didn't use the word anything as a clarifier?
It's because you used Past Tense although there was none in Polish. And "never" is an addition as well ;)