Blog Directory like on Edublogs?

Hi,

How is this directory built? - http://edublogs.org/community/

Are there blogs inserted automatically (when someone creates blog, it goes there) or are users adding their blogs themselves? As I saw, there is manual adding page of blogs.. Can this be done with CustomPress? If so, how is it on front-end?

If it's absolutely custom coding, than sorry - I'll make it with CustomPress, just curious about that..

Thanks