Logging in after four years

Long time no see. I've been busy with many things and projects so I am just discovering today that Steemit is still alive and kicking, which is great. Clearly a lot has happened while I was away.
Incidentally, I just discovered that Steem Dollars are worth way more than their original peg (?) value.
Anybody cares to explain why, or post a quick recap of key facts in the last 4 years? Thanks.