microblog is a specific term for an individual note post, the act of writing such a post, a blog which is a collection of such posts, and also the name for a hosted service (Micro.blog) for such blogs.
Microblog posts are _short_ with [inline links](http://snippets.today) and styles like a long post. But you can publish them both to your own site and a social network.
The Cambridge Dictionary defines microblog as:
- "a blog in the form of a short message for anyone to read, sent especially from a mobile phone"
- "Microblogs, for example on Twitter, can be for anything from "what I'm doing now" to coverage of serious political events."
While it disclaims responsibility for the examples it offers, the Cambridge Dictionary makes it clear that "microblog" is a generic form of expression, while Micro.blog is one specific application, among others, that permits people to microblog.