Read/Write Web, a excellent blog I follow had a post which excited me "SilverStripe - Open Source CMS Has Support From Google". For a moment I thought wow, that's unusual for Google to support a CMS, whats going on until I found out it meant:
Another interesting thing about SilverStripe is that it recently got support from Google, in the form of being a part of the Google Summer of Code project
Oh is that it? Bear in mind that Plone has participated in the the Summer of Code for at least 2 years and has had quite a few contributions. So has Django. In fact the list is quite long and among the CMS's in there includes: Plone, SilverStripe, Joomla, Drupal and probably a whole bunch of other one's I've never heard of.
So calm down everyone, nothing much has changed. If you want to talk about CMS's take a look at Plone which in maturity is far beyond most of the other CMS's you've seen in the comments.