[CMS] Hanena as CMS

CMS, Content Management System, is my research theme.

I have an experience of using Nucleus to serve a small enterprise blog site, which is still exists somewhere. (^^;
Nucleus is easy-to-use CMS. The running cost, however, somewhat big I think.

I'm interested in the Hatena's internal architecture.
I read DB Magazine. But that feature was mainly focused on the database desine and architecture. I want to know more about Hanena as CMS.