Are IP addresses really helpful in moderation? Moderation usually pertains to the content itself, meaning you would want to block certain content from being posted regardless of the IP that sends a request. Maybe you extend moderation to include banning users, but at that point you have more specific data than IP addresses (like usernames or user IDs).

You can target a list of suspected spammer IPs, though that's often a losing game of cat and mouse where you end up missing some spammers and catching legitimate users in the crossfire.