He makes a good point about social media sites:
My blog’s older than Twitter and Facebook, and it will outlive them. It has seen Flickr explode and then fade. It’s seen Google Wave and Google Reader come and go, and it’ll still be here as Google Plus fades. When Medium and Tumblr are gone, my blog will be here.
This really is true. If you run your own blog on your own domain, you have complete control over it. I believe this explains why email is ubiquitous, even if it has problems. It’s not controlled by any one company, and as such, it will live on. I guess I could also bring up the fact that you can host your on email with a host provider and have control over that too.