I have been fixing up tagged posts on my Wordpress.com blog ATMac with the fancy new tag stuff in 2.0 (Yaaaaaaaaaaaaaaaaaaaaay, BTW!!! I love it!!!!) and discovered that if I edit a post and then repost it, and the reposting *fails* (in my case because the internet connection dies a lot) then there is a Growl notification of the posting failure, but the post is not marked in any way and stays in the post list for that Blog in its updated state... if I don't look for the success/failure Growl notifications, I would not know that the post had failed.
I think this should be marked visually somehow (in the post list? draft folder is not quite right ...) so I know to try again later. Especially if I want to edit a lot of stuff offline.