Why Is Asterland So Similar to Eberron?

When I first saw the Eberron campaign setting, I asked myself the same question. Some similarities you might have noticed include:

Asterland Feature	Eberron Feature
Elemental Constructs	Warforged
Moving Tatoos	Dragon Marks
Magic-powered Airships	Elemental-Powered Airships
...and MANY more

I have had my fantasy world online since at least 1998, according to archive.org, long before Eberron was submitted as an idea for a game world. I suspect that Eberron was "inspired" by Asterland, but perhaps it's just a case of like minds thinking alike.