Well... it appears they are starting a group to help people find each other to take cruises together. Obviously, those people are called "cruise mates".
We are "CruiseMates" and while many people do use our site to find cruise mates that is not our primary purpose, and we don't make money from it or anything. We are really more concerned with providing good articles and forums.
So, I really don't mind a few people getting together to possibly share rooms on cruise ships and having them call themselves cruise mates. I don't consider it competition.