We don't have a policy but we should
From the answers and comments on this question is has become clear that we have no standing policy on signalling edits in text. By the votes on the answers it seems as though people are mostly in favour of us having a policy but can't agree on what it should be. Here is my suggestion.
Feedback and improvements on this post are encouraged. I hope we can find a policy we can agree on and use to improve the quality of the site.
Avoid signalling edits where possible
In general terms the "edit:" syntax should be avoided, there are some exceptions however. Let's consider some use cases:
Signalling edits in questions
Using the "Edit:" syntax should be avoided in questions where possible. It is not required for:
- Edits that do not modify the intent or meaning of a question
- Edits to add an example or clarify a point
- Edits to correct typos or clear up wording
- Edits to include information from comments
Under some circumstances it may be appropriate to indicate an edit was made within the text. These circumstances include:
- Making a significant change which may invalidate answers already made.
- Making a change which may affect users voting decisions
- Other edge cases at the discretion of the community.
When making edits:
- Use the "edit summary" field of the edit window to summarise changes
- Incorporate the changes to create a single cohesive post. Do not create a separate post under an "Edit" heading.
- (Optional) Leave a message "Question has been edited to..." at the bottom of the post if you feel it is required. Comment should indicate the intent of the change not a list of the changes made. Revision history can be used if users wish to see the differences.
- (Optional) Comment on any answers to prompt the authors to update in line with the new changes if required.
Signalling edits in answer posts
"Edit:" syntax should not be used in answers. Edits and improvements should be incorporated into a single post that is the best version of the post. Edit history can be used to find previous revisions. Unlike questions there is no need to be concerned about invalidating answers with edits here.
The only exception is when a significant revision is made that contradicts the original answer and may effect voting. I would prefer that these answers were deleted and a new answer posted but if that doesn't happen a small note can be included to state:
This answer has significant changes since an earlier revision.