Easy as PIE, it is a new form of digital currency here on Steemit it but many still DOUGH know all about it. Allow me to just to add to Brendan's explanation. POCKET is Steemit's first token and it was designed to last for the next thousand years. Unlike Steem and Steem Dollars, there will never be any more POCKET tokens created so it really is like digital gold here on our platform. Folks that have accumulated a lot of POCKET tokens are known as "Sea Otters" here on Steemit. You can trade the tokens outside of Steemit on Bitshares for other cryptocurrency and the value is somewhat less than Steem at the moment.