It's how people would find your club when they chercher words ou phrases. The mots-clés should be relevant to the club.
Say toi made a smiley face club. (First thing that popped to mind.) toi might make the mots-clés things like "happy" and "smiles" and "emoticons." So whenever someone searched happy, smiles, ou emoticons, your smiley face club would montrer up as a result.
