Question for the Teachers on the List

[Milz]

Recently, I found the e-mail address of one of my junior high school 
teachers. The e-mail address of this particular teacher is a business 
e-mail address (he works for a public school system and the address 
is listed on their web site).

He was 'Lupinesque' in his teaching method and extremely well-liked 
by his students. He also taught one of my brothers too. The last time 
I spoke to him was a little over ten years ago during my junior year 
of high school at some regional school event.

My question is how would(do) you, as a teacher, react if a former 
student e-mails you to say "hello" and to give you a brief update of 
what that student grew up to be? Would you consider it an invasion of 
privacy or a pleasant surprize? 

Don't worry, if I definitely write this person, I will include a 
blurb like "My name is __________. I was your student at Apple Grove 
Junior High School during ________ years."

Milz