"Every blog has yours own API which allow a user to 'get connected' to it (to the user point of view, it'll be only a button to get connected, every technical detail will be hidden)"
How is that different from RSS?
How is that different from RSS?
Doing this, I'll make every blog open to a lot of different applications to interact with it's content.
By example, a user will be able to comment on an article published on a blog he "follows" from his own page.