Basically STEEM is like the bitcoin that runs the site.. but you don't get paid STEEM for anything.. just Steem Power and Steem Dollars (I'm pretty sure).. and STEEM is like the stock that trades on sites like Bittrex and Poloniex, however it is not currently on Poloniex..

I have converted Steem Dollars to STEEM, but still haven't received what I think should be like 4 STEEM currently, but it does say it can take up to a week.

Also on the other side STEEM DOLLARS can be used to send whatever the value is in Bitcoin straight to your bitcoin wallet using blocktrades.us