Better question: who’s acting first?
I’ve run my Skyrim adventure module a couple times now, and it’s in a chatroom which is a window that shares my desktop with 3 or 4 other GMing-related windows. Which means: it’s a small chat window. So when a fight breaks out, I’m lucky to have even one of the contest results on my screen at a time.
I’m thinking I can resolve this in a way that would be good for both chatrooms AND tabletop games. The initiating character, by definition, initiates each action (he’s the one taking his turn). So when he announces his action, everyone else has a moment to react, and say so. If you don’t say anything, then everyone who DID announce an action or reaction rolls at the same time. Then the GM goes around the table resolving the actions in the standard order: initiating character, highest initiative, next highest, etc.
What will have to come out in playtesting: does it slow the game down to pause and see who’s reacting? What’s the difference between willy-nilly act-and-roll, versus announce-then-roll order?