When my 20th reunion came around a few years ago, I heard about it quite indirectly- from my mother, who happened to run into somebody else's mother at Local Grocery.
When I looked at the 20th anniversary website, I was listed among the missing- students who, in spite of the best attempts of my classmates, couldn't be found (and this was well into the internet age).
I found this amazing, for many reasons:
1. I haven't changed my name.
2. My parents still live in the same house and have the same phone number as when I went to high school
3. My neurology practice is less than 5 miles from the high school I went to.
4. I am listed in the yellow pages under my own name.
5. If you type my real name into Google, one of the top hits is for my practice's web page.
So I personally felt the fact that none of them were able to find me was a comment on THEM more than ME.
And nothing further need be said.