Most Greeks lived by the sea and therefore worshiped the god of the sea. They thought that if they worshiped him they would have a pletaful fishing. That's why famers worshiped demeter. It's all about what you did for a living back then.

Because he was the god of the sea duhh

He was called the Earthshaker and not only ruled the sea but the surface in general. When he and his two brothers split responsibilities over the the world, Zeus took the sky, Poseidon took land and sea, and Hades took the Underworld beneath them.

Some Christians like myself believe that this was an aspect of God recorded in Habakkuk 3:3-15 of the Bible.

Yes. Both Hesiod and Homer talk about the 'trinity' of Zeus-Poseidon-Hades and their different allotments. There are several theories on this: That the 3 Greek gods are all different facets of the one supreme being; and that maybe Poseidon was imported from somewhere else. But in the Mycenaean Linear B tablets at both Pylos and Knossos Poseidon is listed well ahead of Zeus and receives a greater number of votive offerings. So Maybe Poseidon was the chief god in Mycenaean times (ends about 1250 BC) and then something happened to cause the rise of Zeus by Homer and Hesiod's time (c. 7th Century BC).

That is true

He was called the Earthshaker and not only ruled the sea but the surface in general. When he and his two brothers split responsibilities over the the world, Zeus took the sky, Poseidon took land and sea, and Hades took the Underworld beneath them. This i believe

but not this. (Some Christians like myself believe that this was an aspect of God recorded in Habakkuk 3:3-15 of the Bible.)

Besides Poseidon, an early Christian-era apostle known as Paul even quoted from the Hymn to Zeus when speaking in reference to the God of Abraham (Acts 17:28).

Whether you or other modern day people believe it or not, it's still a reality that the God of Christians and Jews was previously worshipped by pagans including the ancient Greeks.

To me, many of the Athenian poets were prophets like Balaam, a gentile whom God spoke to despite his spiritual values and practices.