Every guild has it's own purpose. Whether to lead the in-game leaderboards, help it's members level or collect new items, or simply act as a medium for whether others can meet and hang out, every guild in the Caribbean is different from it's companions in some shape or form. Just because the guild you are in does not fit you well does not mean that guilds have no purpose, it just means the guild you are in has no purpose
to you.
Before going on a guild hunt, consider asking yourself just a few questions: how big do you want the guild you are in to be, and how active? How personally connected do you want to be with your guild mates? What do you want the focus of your guild to be? So many questions, but in the long run answering all of these for yourself before searching for your new home will make things a lot easier for you.
The great thing about these forums is that they provide a general way for pirates to showcase what their guilds are all about. After you get an idea of what you want out of a guild, cruise through the threads and subforums in the Guilds and Clans section here on POF to see which guilds may suit you. If you find one that fancies your eye, private message the original poster of the guild's information, or any one of it's Officers, and I'm sure they will be more than glad to help walk you through how to join their guild, and what to expect.
Happy pirating!