Blogs that have been closed due to inactivity are listed here. The length of time a blog is inactive before it is added to this category varies, but is typically more than four months.
If there is a need to continue a discussion of a blog, commenting can be re-enabled as long it was not originally shut down due to a flame war or other disruption. Check the edit history of the blog to see why commenting was closed and/or see if a comment was posted stating why commenting was disabled.
As an alternative to resurrecting an old blog, consider creating a new blog.