I just had a situation where the board was so slow that I got a time-out error when posting. I clicked Submit again, and this time it went through-twice. What gives? Will I always end up with a double-post when timing out on a reply, or was this a fluke?
Generally speaking, your first submission will almost always go through- even if you timeout and never hear back from the board itself, your post probably reached it, since most of the slowdown is on the MB server itself. Generally speaking, the best thing to do is to assume it went through, open a new window, and load the thread again in the new window. If your post made it in, it’ll show up.
If it reaches the “thank you for posting screen”, then it’s a lock to have gotten through. Otherwise, it is best to check.
Although I was pretty sure they had a filter for *identical[/] posts. But that won’t help if you use the time to touch up the typos.
Likewise, if you have your browser set up to “warn me before accepting a cookie”, you’ll notice that the MB software send a couple of cookies to you in response to your posting. Since the board is not psychic, it can only be sending these cookies in response to your post arriving- i.e., if you get the warning for them, your post has arrived.
That depends on your browser configuration, though - lots of people find those cookie pop-ups icredibly annoying.
The “filter for identical posts” is called a “moderator”. 
And AFAIK, they only swing into action for really egregious examples of multi-posts. I think they think it’ll be a learning experience for us, to have our double post sit out there, in front of God and everybody.
Eh, Frobozz, always trust the CGI to grab onto your post, even if it times out, and it’s a good idea to go back and check the thread to see if your post is there before you re-Submit.
The way I visualize the CGI and the server is like a vacuum cleaner. The opening of the hose (the CGI) sucks up the post, but then on the way down to the bag (the boards), it sometimes gets clogged a little, and has to sit there in the hose (the server) and wait, but eventually it does slurp on down. And nobody has to fish around in there with a coat hanger, either. Amazing!