Let's say you've got a new player coming into a Forgotten Realms game. Because there is SOOO much information out there regarding the Realms, you don't want to overwhelm them.
Apologies for resurrecting an aged thread, but this is the exact position I find myself in. I have just joined a Pathfinder game set in FR. I casually asked the DM 'what should I read up on to get a clue?' to which the reply was 'start with the wiki'. It is mindblowing, so seeing others in a similar position being given guidance on this stuff is a great help.