I see a number of posts that have a comment that say "Edited to add the thingamajigger". Are these kinds of comments encouraged? Are they actively discouraged? Is there an appropriate course of action to take for them? Should I flag it as noise, since there's already an edit description? Are they too small of potatoes to worry about?
If someone posts a comment on your post saying "Hey, I think you should add _____ to your question to make it clearer", then I think it's helpful to add a comment to notify them that you've updated your post.
Other than situations like that, I think they'd just be useless noise. We can already look at the edit history to see what you've changed
There are several cases where a comment after editing may be warranted:
- I see a question that is not very clear so I edit it to try to clarify (making some guessing and assumptions along the way). I will leave a comment to let the OP know that I have made some assumptions based on what I think he/she was trying to say, and he/she is free to undo the edit if I have made an incorrect assumption.
- I see a edit to a question (presumably to clarify), and in doing so, the edit has invalided several answers. A comment to the each of the answerers should be left to inform of them of the edit.
- Someone makes a comment suggestion on my answer. I will usually leave a comment to let them know I incorporated their suggestion, or fixed the error they found. This is especially true if they indicated the voted a specific way because of the issue.
Most anything else is noise and is not necessary. The edit history does capture the edits, so mentioning it in the comment when not using it to ping someone is not needed.
I would flag other occurrences petty quickly, and if it fits in one of the above guidelines, I would flag it only after a few days to make sure the note was read.
I think such comments could be useful if directed to a specific user. For example, if you edit your answer and add some important data that you think the OP of the question should know about, it's useful to write a comment directed to the OP, in order to notify him/her that you edited the answer.
This is not a hypothetical scenario. I actually edited an answer today and wrote a comment for the OP.