What is "traditional" muay thai?

I've been to Thailand to train, watched fights at Lumpinini a few times. Been to the smaller local festival fight shows.

Pretty much every muay thai gym website in the world has the words "traditional" muay thai somewhere on it.

So what the hell is "traditional" muay thai? If the reader knows what muay thai is, then they know what muay thai is. So is "traditional" just a promotional buzzword? What does it represent stylistically in the art?