I thought it would be helpful to consolidate the recommendations concerning double posts.

First (and most important) - Always assume that your Submit button has worked correctly, no matter what sort of weird message you get back (and there are some doozies). If you submit again you will almost always get a double post.

Second - To check if your post was received, go back to the main forum page and hit your browser's RELOAD button. This will load a new copy of the main page. The BACK button usually just refreshes the page from the browser's cache, so it won't show any changes.

Third - You should see your appropriate thread name at the top of the list, colored so as to show it has changed since you last loaded it. Just click it again, your message should be there. If it's not there, it's OK to post again.

One more tip - If you've entered a long message and are afraid of losing it, select and copy it to the clipboard. Then, if you're really concerned, you can paste it into Notepad (or whatever) and save it.