Seems like a great question, doesn't it?
Why would someone want to create an Encyclopedia of Famous Marines on the Internet?
More than anything, the answer is really, "Why not?"
Who else is doing this? Sure you may see an article here or there which lists famous people who are also Marines, but these lists are short and thus incomplete.
As a Marine, what I can tell you is what I've learned in the Corps: If you're going to do something, then do it with excellence and it will get recognized.