Hi Tony - unfortunately, there doesn't seem to be an 'edit' function available. The best I can find is after you have posted a question, if you go back to it, there will be a pink box underneath which says something like 'additional information', or some such - if you click on that you can add additional info, including making a reference to correcting something in the original but you can actually edit the original. As for line breaks in comments - not sure - you can put them in when doing answers, like here but not sure about comments. Have you tried typing up your comment in a word processing document then cut and pasting it in?? actually I tried that once when I wanted to insert some formatting but it didn't carry over, so I have probably just answered that question. It is the one thing about this interface that I wish they would upgrade to make it more friendly.

Not as far as I know. In my opinion it's a big problem on italki, and different from most other social sites. I have no idea why it's that way.

I think the idea is to simulate a school environment, where you can't ask your test back a few minutes after having turned it in, just to make a few quick edits.So, to push you to pay close attention to your writings, like, re-read it all before hitting 'send'.