We celebrated our 5th there a couple of years ago. We got the buttons and wore them the whole week. Several people said Happy Anniversary because of them. We also added the celebration to each of our ADRs. Most places it didn't mean anything, but some would put confetti in the shape of hearts on our table or something else small. I've also celebrated my bday there, and you get much more for a bday than an anniversary. But it was still a great experience, and my DH who is no where near the Disney fan I am said he thinks we should make it a point to spend every multiple of 5 there.
Have a great time, and Happy Anniversary!!!