I agree that the volume uptick was the giveaway to steem's breakout above $4. I wrote about this in my recent post, "Steem's Blue Sky Breakout Above $4".
Notably, in the last few weeks of December, steem's daily trading volume per Coinmarketcap was hovering around $6M, give or take. Then it suddenly jumped to over $20M soon after Dan's 12/31 post regarding improving governance at steemit.
At the peak of the breakout run, the daily trading volume exceeded $100M. It has since settled down and the price of steem has pulled back some but is still holding above the $4 breakout level, which is a positive for the bullish thesis.
It is imperative for Steemit Inc to capitalize off of this momentum and roll out SMTs and innovations on this platform if they hope for the bull run to continue.