I discovered something this morning. If you type out a post and click submit, most times it goes through fine and it posts.
If someone else posts while you were typing, it gives you a message "another reply was posted and you can review your post".
Either way you are fine.
BUT, I found out the hard way that if you happened to click "submit" EXACTLY when someone else submits theirs, then yours just vanishes!
And by Murphy's Law, this tends to happen when you have just typed out a long reply (this happened to me) and I had to retype the whole reply!
So now, before I click "submit" I use "Control A" which selects all the text, and then I copy it, and that way if it does vanish, I can paste it in to a new reply.
Bruce