The STEEM cryptocurrency is based on a Social Network(Steem social network that can be accessed through steemit.com ). The holders of Steem currency are, in fact, the owners of the social network.
Mining is done in this way: User posts are voted by steem holders (the more you have the more your vote worths), and the best rewarded posts also have higher exposure.
My STEEM profile
https://www.steemit.com/@duartenunesHow to create an account?
Option 1- with steemit.com (takes about 1 week for approval and is patchy (some are never approved))
Option 2- A friend already at steem creates an account for you by donating or delegating to your account some of his steem through paid systems. I can do that for you, I ask for a symbolic payment of 50 euros and I will donate some steem so you have enough broadband to post, comment, vote, etc, without constraints.
Hugs
Duarte