This is going to be a possibly disappointing post, because
VIII. Variations on Poseidon (aspects, regional forms, etc.)
This is one of those things that you can find if you visit places like theoi.com. I may sound like a broken record by now, but we are fortunate to have source material that others don’t have, and so much of it is online and free and there’s no excuse not to use these resources!! I love reading about this stuff; I’m not so much interested in just regurgitating what you can find elsewhere. Check out this page and this page referencing Poseidon’s historical cults.
IX. Common mistakes about this deity
This is less about common mistakes and more about my own pet peeve, and it goes beyond just Poseidon. I realize the need for shorthand, but I cannot stand the X the god of Y. I know why it’s done, but oh, it gets under my skin. Yahweh is not spoken of as the god of y. He’s just god. Aphrodite the goddess of love. Poseidon, god of the sea. It lends to a narrow superificial understanding of our gods. Poseidon is known as a god of the sea, a god of earthquakes, and of horses — and these are important parts of Him, but it’s not all, and it does a disservice to our gods to think in those terms.
This is short. Words are difficult today, and I’m just not in a place to be annoyed, so, I’m moving on now. 🙂