In the "Message Body" I don't see that "<span id=INSERTION_MARKER>"
In fact all I see is a blank, and then I'm unable to type more. The pasted text is wrong, but it's also invisible. So I can't erase it. This compounds the problem because I don't just loose my long text, it vanishes, and then I can't untangle the indivisible text from what I had already typed in manually.
OK, sometimes I'll be typing a lengthy response for a given discussion thread and I will have my browser fail on me for some reason or another. Usually this prompts the loss of my whole text, it's happened to the best of us...
Anyway, my solution is usually to type up important long-winded texts outside of my browser, and then copy-pasting it in. That way I'll have a fundamental back-up until I'm sure the info has been posted.
When I do this on CNET forums... something weird happens. For example, I was looking up an AMD Athlon X2 processor for another thread. I had it's long detailed name listed in google's search bar, so I just copy pasted it into this tab, and this is what happens.
Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic