Hero: It's not against the rules to be active if the conversation is going smoothly and without an abundance of spam. It is totally against the rules to spam though.
That said, I feel like I should make a note that how active a clan is is completely irrelevant to the clan's quality. My old clan Verdict hardly had more than 100 posts in its thread before it was made official. Similarly, clans like vibe or doc would never shut up and were pretty great as well