We've now posted a general announcement about the availability of packages on April 4, 2013: http://www.postgresql.org/message-id/CAN1EF+x0dmwMFuJGWuXMiR... and http://www.postgresql.org/about/news/1454/

As stated in the announcement and Tom's email to -hackers, the reasons for advanced notifications are as follows:

* People watching for vulnerabilities and contributors are going to notice that we've stopped automatic updates -- it's better for our project to just tell them all why

* Upgrading relational databases is often not trivial -- we want to give our users time to schedule an upgrade rather than just dropping an important update suddenly