MoonlessNights's Journal: What does the Slashdot journal do?

I am having trouble finding information explaining what this feature does. The UI makes it sound almost like it is connected to the submission flow but also seems to come across more like a minimalist blogging system.

Is it both: a blogging system which can be easily promoted to a front-page story, if others find it insightful?

If anyone can point me to some authoritative information, that would really help.