Welcome Sari.
Steemit is the first Decentralized Social Media Platform that runs on the blockchain. Since there are no Owners, When subscribers Post, UpVote or Comment on a post, we are all helping the STEEMIT network to stay running and to keep it growing,
For that, the Network rewards you with STEEM; a cryptocurrency with actual value in digital cash just like Bitcoin, Ethereum, Litecoin, and many others that generates either value to the network by the user keeping it in the STEEMIT network, or by trading it in the Crypto-world generating Hush power to the Network.
Here is the STEEMIT white paper. Please read it and get familiar with the concept of DECENTRALIZATION, BLOCKCHAIN TECHNOLOGY, CRYPTOCURRENCY MINING, SMART CONTRACTS, NODES, AND TOKENS>
You will do great here.
https://steem.io/SteemWhitePaper.pdf