Just a quick reminder in times when Steemit.com is not available - like right now.
Steemitstage.com is the official development version (testing of new features) of Steemit.com maintained by Steemit Inc.
I'm giving no warranty here, but you can do everything you normally do on Steemit.com - at Steemitstage.com.
However, when possible - it's better to use Steemit.com