I hope this is an indication they're considering a switch to Git for the future. It makes a lot of sense to me consider the distributed nature of Automattic's workforce and the large number of contributors to the codebase.
http://markjaquith.wordpress.com/2011/05/26/developing-on-wo...
Jesus. I thought SVN had beaten CVS years ago...
And, most disturbingly, there is also https://github.com/wordpress/wordpress, which looks more "official" but wasn't updated since about 1 year.
It would be awesome if WordPress would publish the official stuff under the wordpress github account - there would be less confusion, IMHO.
But to your point, indeed. The open-source community does pay attention to what's on Github. I'd love to see Wordpress move over to github - It would certainly make me follow the development closely and probably fix outstanding issues. Git (and pull requests on Github) make contributing so easy, it just makes sense.
Believe it or not, just because there is a notice that a new version of free software is out, doesn't mean any non-technical person will follow through with the notice.
Kudos on this.