The only solution I can see is making sure you have their email addresses and reach out to them with meaningful emails. They all still have email addresses.

One of my favourite things is reconnecting with people after time apart. With tools like Facebook, this rarely happens any more. It feels weird not to see someone for a while, then you reconnect in person and know too much about what's gone on in their lives. It takes the intimacy out of the person-to-person conversation of catching-up.

I'd rather get the yearly email update from old friends, than to track their lives voyeuristically through the web.