Just this minor thing when I'm writing online on this forum. The edit works a bit different than usual, for example ctrl + arrow left/right doesn't jump one word at a time, but the whole line. Just nitpicking. But for longer posts it's really handy to select or skip whole words at a time via keyboard (and somewhat faster than one character at a time).
I also noticed the tags have a drop-down list that automatically shows when you start typing tags, and it will select the first one when you try to separate tags with a comma, even if that's not what you wanted to write. Unless you write something unique or maybe have it in apostrophes.