From the Caosity website:
It turns out that the release of Centos-3.3 was so popular, that it threw us way over the threshold of our ISP's, and now we are stuck with a _very_ large bill (as in an estimated 6TB of transfers). While in one hand I am ecstatic that we are so successful, but on the other hand, that is coming out of the developers pockets. The developers should be the last ones footing these bills (and this one was very large).
You can help. Please consider a donation for each of the systems that you are using. A reasonable donation we think starts at $12US per system per year.
That money is only spent on infrastructure and development. $12 is much cheaper then a magazine subscription, and if everyone contributes their share, we will be able to grow our infrastructure to better handle our growing user base, and continue to provide software to the community.
Please visit http://www.caosity.org/contributing/ to do your part.