Not only is today's outage not mentioned, but neither is any of of the planned maintenance in the last year. Since the blog appears to be abandoned it should be removed from the banner because it's no longer a current source of information.
stackstatus.net is used for communicating planned maintenance that we expect will cause an outage (which we haven't had any of in a while, as you noted) and posting of public postmortems (you can expect to see one for this outage).
In the middle of an unplanned outage, we just post to Twitter instead of also drafting a blog post; see the StackStatus twitter account for the most up-to-date info, but the blog should still get updated with future planned maintenance and postmortems.
The problems from 4 years ago have been addressed at some point since. The banner has a working link to www.stackstatus.net, and that site did contain information about last nights planned maintenance window.