It surprises me a lot that there are popular questions like these ones:
Just to name that particular topic. With the same emphasis I can recall that, long time ago, I wrote a question/answer of combinatorics and its application to poker, because I found several questions addressing that exact topic with a reduced scope of one particular hand.
Although Poker has a wide range of stuff you could mess with, I see a good quota of repeated questions hanging around, which are appropriately marked as duplicate.
I understand there are cases when a duplicate is useful (to an extent, having many synonims for a question is useful), but after reviewing the questions sometimes I'd like to call them to read the manual or, at least, read a kind of source we have in this site.
There is good material here (a notable example written recently by paparazzo) which could serve as a kind of documentation or pinned question/answers here.
Should we (and can we) pin content so the users can read them before posting a variant of the same questions? Do we have an equivalent of the StackOverflow's documentation tool here we could use?