I recently participated in a thred where the initial post was rather short at the time of my comment. A few days later, the original poster edited their post and made it much longer and detailed, which totally changed the perception of my comment. However, newcomers to the thread can't see that the original post was altered AFTER a comment.

It's fairly standard for systems to give an indication that a post has been edited. Jira did it as well, not to mention the wiki. I think this functionality needs to be added (or enabled).