The difference between creating a “post” at MediaCommons and creating a “blog post” is a pretty fine one. In the Drupal universe, a “post” either lands in the site’s main blog stream (by being promoted to the front page) or it doesn’t; regular old posts don’t accrue to individual user blogs. Blog posts, however, do; any user can create posts on his or her own blog if the blogging module is activated, and those posts can be editorially promoted to the front page or not. The blogging module thus enables a bunch of people to be doing a bunch of stuff in different areas of the site, and for different parts of that stuff to be made visible at different levels and in different ways.
We’re hoping that a bunch of folks will start blogging there, whether posting original content or cross-posting from existing blogs. I’ve just posted the first official blog post on the site; I look forward to having it joined by lots more new content — not least, stuff from the big project — soon.