Rules on when it is or isn't appropriate to comment on someone else's manners or behavior. In other words, rules of etiquette for discussion of rules of etiquette, or meta etiquette (metaquette).
Alice: Did you notice how Chad was being super-polite to Dana, but he barely even said hi to Eric?
Bob: Yes, but since Chad is standing right next to you, I'm going to have to question your metaquette skills.
Memetiquette is an unwritten set of rules that each Meme Lord or Meme Dealer has to follow during a meme exchange or conversation. For example, if you are sent a meme, you should send one back of equal value or of the same template. Recieving a tier 10 meme then sending a normie instagram post is considered treacherous in the meme community.
Person 1: " Hey, Person 3 just sent me a meme with no captions. "
Person 2: " Send him a meme from Pubity or some other instagram page "
Person 1: " Have you no Memetiquette?! Thats a high tier meme, you uncultered swine! "