Recommended For beginners: Steem currencies and rewards sum up– 1 min read - Update 0.12.2 - 26 july 2016

Steem is a blockchain-based social media platform. It relies on Steem, Steem Power and Steem Dollars.

- Steem can be traded like any cryptocurrency (poloniex, bittrex). By purchasing Steem and powering it up it into Steem Power, the holder will earns more Steem in rewards and voting power. The total number of Steem doubles each year. Every 3.32 years, a 10:1 reverse split occurs (10 Steem becomes 1) to solve number precision issues.

- Steem Power rewards long term holding. Steem Power is non-transferrable. It can be converted back to to Steem in 2 years and through 104 payments. 90% of the new Steem goes to anyone holding Steem Power. 10% of the new Steem goes to anyone voting on a post or contributing.

- 1 Steem Dollar = 1 dollar value stored. Can be converted back to Steem after 6 days taking account of the Steem/dollars conversion. It can be sold instantly for Steem on the internal market. Holding Steem Dollar pays interest.

Steem rewards you for Posting, Curating, Holding, Saving, Mining (No more liquidity rewards since update 0.12).

1) Posting: Rewards for a new story: Creation of new upvoted content (50% Steem Power, 50% Steem Dollars). Each discussion goes through a two stage payout. The first one is a 12 hours payout. There is a second voting period set to 30 days after the first payout. After the second payout a discussion becomes "frozen". The discussion is no longer editable and new replies are disabled. Users can still vote on comments in these discussions as a "nod" to the author without costing their posting power or awarding reward shares. Create meaningful, original content. Post often.

Rewards for comments: 25% of the total payouts allocated to a top-level post will be split among all comments proportional to the votes the comments receive. Each root level comment has a reward weight which impacts the end payout of the post. Your first 4 posts in 24 hours will not be penalized. After that, they weight is decreased from 100% based on your average posting frequency. Having a frequency just barely higher than 1 every 6 hours will have very little impact, while spamming will be penalized heavily.

2) Curating: When you are among the first to upvote future popular content (Steem Power). Users with vesting STEEM have the ability to vote on posts. If you vote immediately after a post is made, then 99.94% of the curation reward will go to the author. If you vote after 15 minutes, then 50% will go to the author. Any votes made 30 minutes or later 100% will go to the curator. This only applies to the curation rewards (update 0.8). The author still gets at least 50% of the total rewards. Voting Power is rate-limited and decays by up to 5% every time a vote is cast. Voting Power regenerates to 100% over 24 hours. To maximize total Steem Power applied to posts, users should vote on at least 20 posts per day. You can check the rewards of a post by going on the post and changing "steemit.com" to "steemd.com" in the adress bar. Then click advanced mode, Vote details.

3) Holding long term: Steem power earnings, need to commit for at least 2 years.

4) Saving short term: Steem Dollars interest

5) Mining: Steem can be mined (Ubuntu, Windows). Mining requires operating a full node and building Steem from source. A witness is any full node that processes and validates blocks. This is a necessary prerequisite to produce blocks. Once your proof of work is accepted by the network it is critical that your node stays connected so it can produce a block at the scheduled time. Each round (21 blocks) one miner gets to produce a block. A round can take at least 63 seconds if everyone produces a block. The miner queue length is proportional to the difficulty. Difficulty doubles with every additional 4 miners in the queue. 19 witnesses are selected through vote. 4 more are chosen randomly each round. Mining pay is estimated at 4800$ for a full day. I made a post about how Steemstats.com can help for the selection and vote here.

Detailed rewards info:

https://steem.io/getinvolved/
update 0.8
update 0.12
All images used are public domain.
There are often updates, stay updated. Feel free to comment if I made a mistake, all help appreciated. Thanks!