My blog isn't part of a system where its usefulness is just a hook to get me to use it.
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.
The things that will last on the internet are not owned. Plain old websites, blogs, RSS, irc, email.