Just an FYI: I found two links that consistently gave IP Permaban messages, so I posted a thread about it. Seems to have been fixed since then, but no one responded, so I deleted the thread. Not sure if it was just being temperamental or if one of the 20 views was someone who fixed it. Not complaining either way, but it did truncate one of the two links when it automatically parsed it. Seems like if you just paste a link that exceeds a certain length without surrounding it in "url" tags, then it puts an ellipsis in the link to shrink it down, then parses it after it's done that, which leads to broken links. It did this to one of the two links, but not the other.
Maybe this will help, but the first link which it did NOT truncate was 44 characters long, while the second that it DID truncate was 54 characters long. Just a hunch, but I suspect it's using 45 or 50 as a baseline, and that's why it only did the one and not the other. Seems like it should be parsing it as a link, and then truncating it, not the other way around.
EDIT:
I think I know why double-posts seem to be more common too. When you click "Submit" on a post, it looks like nothing happens, but if you look closely at the browser tab, you see the wheel spinning. Might alleviate the problem if you disabled the button or displayed a message in the OnClick event of the Submit button to make it obvious that it's doing something, even if the server takes a while to respond (slow connection, long queue, etc.)