Essentially the blog editing system itself is a user interface.
After logging in, there appears the dashboard systems showing recent updates of the blog, and a toolbar on the left showing actions a user may want to do. Numbers may appear on the toolbar showing number of new posts in that section.
The user may want to add a new post, for example, so he switch to the “Add new post” interface. Then the user can input texts and pictures, change format, choose categories, etc. of the post.
Finally, the user click “Publish” — and a new blogpost is born!