Sometimes you realize you made mistakes or wanted to add something more to make your message more transparent in the response you have posted. We can do that using "edit" function. Just that, if the revision concerns something essential (e.g. typo or technical mistakes in equations) for the upcoming discussions, the other participants of the thread are better notified about. It may not necessarily be all participants, only those whom the revision maker thinks should know (e.g. the OP in an homework thread). For this purpose, what if something like "notify about the revisions" option is added whenever one makes an errata where he/she can specify which thread participants should be notified?