The blog section notes how many unread items you have on a section.
But when you enter that section there is a listing on the right side called "Latest Comments" which never seems to match where the actual most recent comment is posted.
For example, today my status showed 1 unread item in "The New Network" blog.
Open that blog and the "Latest comments" shows:
Jibran Rafat(anon) on: The Next Chapter in the Converged Supercore
But this is already read by me and the true latest comment is on the second page:
by Charuhas on the blog post "Decoding SDN"
This makes finding the real latest comments a pain, and sometimes I just give up looking for them and mark all as read.