Is there a way to get rid of or change the discussions after they are posted?
E.g. I failed to attach a youtube video link twice, so I ended up publishing two identical introductions to a non-existent video, which I could not remove.
Yes, you can edit or delete discussions after they are posted. Just view the item you wish to edit and click on the "options" button at the top of the discussion on the right-hand side. You can choose to edit or delete.
If you have trouble seeing this drop-down menu, disable any pop-up, ad or image blockers in your browser.
Hope this helps.