The wonderful thing about STEEM is that a large percentage of it is held in STEEM POWER (over 90%).
STEEM can immediately be converted into STEEM POWER, but STEEM POWER cannot immediately be converted into STEEM.
Therefore, 90%+ of the STEEM tokens can only be dumped via 104 equal weekly payments over the course of 2 years.
The volume on exchanges represents under 10% of the STEEM money supply.
That is why it took such a little amount of volume to be pumped so high.... most STEEM it is locked up in STEEM POWER.
Owning more STEEM POWER gives people more sway in the curation of content, while at the same time allowing them to earn bigger rewards for doing so.
Owning STEEM POWER is a long term investment in the STEEM ecosystem.
I suggest reading the whitepaper. They have created a very elegant ecosystem. https://steem.io/SteemWhitePaper.pdf
Alternatively, there is a lot of information linked here: https://steemit.com/wikiversity/@boardwalk-steem/lets-start-a-steemit-resource-repository