For me steemit was offline for at least 30 minutes a few hours earlier (12GMT??), with a 504

edit: I was also unable to post a comment certain comment, regardless how often I F5-ed or even opened a new tab by clicking on the link under replies.
Then I posted a "test" comment - that worked. I could also copy in the not-working text.
So I guess the problems also have something to do with what steemit saves as draft. Once I got "Transaction broadcast error."

edit2: some problems with this post edit, including the error. (which is why I made a second comment, first comment could not be successfully edited)

edit3: had the transaction broadcast error again and something popping up on lower left "e is null"