Three years ago I posted a question about a Confederate flag obscure design .
At first there were some votes to close it (at first I didn't really know that it whas a Confederate flag either) but it turned out to be an acceptable question that had an excellent answer.
When I accepted the answer I made some compliments to the answerer for his effort. I usually do this and they usually don't get deleted. These complimentary comments were a bit longer than usual, but the reason was that they contained additional information about some of the flag's details, such as its gold trim.
Actually, this is not a complaint. They were not very important comments and were made three years ago, but I would like to know if there is a definite protocol on this type of "thank you for your response" comments.