Firefox 18.104.22.168 it completely screwed up my Blogger posting in Fox - nothing happened on clicking Edit HTML or clicking Preview.
I could Save as Draft and even Publish a full post from the Compose box, but if I tried to edit my saved draft the compose box flashed up with the text for a second, then went blank.
My Technorati tags box completely vanished too.
But there were no problems with the post editor in Blogger Beta.
However, I found that when I upgraded to Firefox 2 it was all fine & dandy again. And all my other Greasemonkey userscripts seem to be working fine too.
So that's the answer if you just got the security update for Fox and then your classic Blogger posting got messed up - use Firefox 2 instead. (Or switch to Blogger Beta, if you can - i.e. if you don't have a large blog or team blog).