Start with The web is the social network. For people who have grown up in the era where the web is dominated by Facebook, Twitter, and do-everything-for-you services like Medium, this is a useful reminder that this isn’t quite how the web used to be, or – important! – ought to be.
Next up, read Brent Simmons full post on why micro.blog is not a rerun of app.net. App.net was essentially an attempt to make a more open, less generally ghastly version of Twitter. Micro.blog reminds us that the web itself is the social network.
Finally, a useful guide on what to post on a micro.blog. The answer, really, is pretty much anything you want to use it for! You can use it to replace Twitter with something that lives on your own domain. You can use it to replace Tweetstorms. You can use it to replace Instagram. Or you can just use it to do some old-fashioned blogging. S’up to you, really.