I have been on the floor now for one year after a 20 year break.

20 years ago, the definition of a personal foul was something like, "contact whereby the player initiating contact gained an ADVANTAGE over an oponent because of the contact.

Today (4-19-1), the definition is, "illegal contact...which hinders an opponent from performing normal defensive and offensive movements."

Quite frankly, I liked the old definition better.

Can someone enlighten me on the history of this change and whether you still hold to the Advantage theory?

Is this kind of like the difference between "reffing the defense" vs. "reffing the matchup"? ;)

I think it's just another way of stating the same philosophy. Advantage/disadvantage is still used in determining a foul. Perhaps they thought the language needed updating a little by adding the term "illegal contact". Perhaps some of the older er, I mean more experienced people have a direct knowledge of the history of that rule. But I've been around long enough to know the basic philosophy hasn't really changed.