Hi,
Very informative post. In my opinion, In as much as this time zone is a fact, Some bloggers might want to consider their niche.
Example, A blogger that blogs about photography should consider the fact that photographers, especially event photographers work more on weekends covering wedding and Thanksgiving events and may spend time sorting the pictures.
This is not really the same for civil servants or workers that work during the week days.
In essence, one should be conversant with the interconnecting culture of the niche he or she is blogging about.