There were several zero day updates released with CentOS 7 (1511) today,
as well as the newer RPMs that exist on the ISOs as part of the main
release.

We released Continuous Release (CR) announcements for those RPMs as we
released them to the CR repository.  For anyone interested in those
announcements, they can be found here:

https://lists.centos.org/pipermail/centos-cr-announce/2015-November/thread.html

https://lists.centos.org/pipermail/centos-cr-announce/2015-December/thread.html

As you can see CR updates started showing up 30 November while the
actual release happened 2 weeks (or so) later.

The normal goals for CR are 2 weeks and release is 4 weeks after a RHEL
point release.  If you want to get the CentOS update 2 weeks early, read
about the CR repo here:

https://wiki.centos.org/AdditionalResources/Repositories/CR

Thanks.
Johnny Hughes