The right question is what you can gain from it.
There have been accusations all over the place that Steem and Steemit are a scam (see here, here and here for example). People have also noticed that the creators of Steem are powering down. But even if Steem is a scam, people are still making money off of it right now.
So what should you do?
The cardinal rule is to not risk what you can't afford losing. Other than that, you can try to assess the risk yourself, and you can refrain from investing if you think the risk is too high. You can also power down and cash in (eventually...).
But posting, commenting and voting won't cost you a thing! So regardless of the possibility of Steem crashing tomorrow, if you play your cards right, you can still make some money off of it.
Be smart, be safe, and don't panic!