@indigo TL;DR: It's like Plurk, Twitter, or 10C but the way you originate posts to the service can be different.
To participate on the service, you need to create a profile, which gives you the ability to respond to other people's posts, set a profile picture, and so on. SO far, so good.
You can originate conversations in one of two ways:
- On a micro.blog hosted microblog, which you pay $5/mo for the privilege of having. Then the service operates more or less like 10C, Plurk, or Twitter.
- On your own blog, which could be literally anything that spits out an RSS feed. This option is free, but "some assembly required."
It's that last option where things get confusing, but is what is appealing to a certain population of the Internet.
My originating posts to micro.blog appear on a WordPress site I set up specifically for that purpose [microblog.phoneboy.com]. I post to it just like a blog. The micro.blog clients for iOS and Mac can interface directly with my WordPress blog, which means when I use them to post, it looks just like using a Twitter/ADN client. I can use any Micropub or WordPress client to post to my blog as well, which will cause a post to show up on micro.blog.
Updates to my microblog are read through my RSS feed and propagated to the rest of micro.blog, which also caches my updates. Which means there's a slight delay before a post I make shows up to other micro.blog participants.
When I response to posts on micro.blog, they are stored on micro.blog, exactly the same as if I was responding to a post on Plurk, Twitter, or 10C. Doing some additional things [phoneboy.com], I've made it so the conversations around my micro.blog posts are imported as regular comments on my own blog.
Why bother doing all this? If micro.blog were to go away tomorrow, I'd still have all my posts and the conversation around them in a usable format with zero work on my part. Obviously any conversations I had with others around their posts would disappear unless they did something similar to what I did.
I hope that helps a little bit.