Teach me! How do you keep in touch with people on the go? This is the only thing that has stopped me from dumping my iPhone altogether. I sometimes leave home without it but I end up relying on others for coordination, etc -- which means I haven't liberated myself so much as fobbed off the responsibility to others.
I don't have social media (besides HN), so my main contact with people who aren't in my immediate vicinity is through sharing photos directly on iMessage and the odd article-inspired rant.