One:
A possible reason is that SBD has been pumped, and this in turn is pushing up the price of Steem.

If the SBD value is much higher than $1 then you can make a great yield by buying and powering up into SP and posting - 10% or 20% per month depending on the Steem / SBD ratio.

If this is the reason then there will be a natural equilibrium reached as Steem rises towards the SBD value, or as SBD falls.

Two:
People have started to talk about Steem because it's now established and actually thriving as a new economy, rather than fading away. With SMTs on the way that's a huge addition. There are also DTube, Utopian project, Zappl, Steepshot and all the developments that are actually much further advanced than competitors.

Three:
It's going up because it went up yesterday. That'll happen until it stops going up. Because crypto.