Why not just send out an email to each person in your address book that says "I just wanted to make sure I hadn't lost your email address."?
Because 50% of the people in my address book are business contacts, and it could easily be misinterprested as highly unprofessional, given my relationship with these people, if I were to send out an email asking them to confirm their email addresses;
The other 45% of the people in my address book are friends, both new and old, most of which would respond back with a "How are you? it's been such a long time...What are you up to these days?". There's no way I'd want to sit down and respond back to all of these people.
Anyone else have any thoughts?