This is a known bug. We’re working on a fix. If you try to comment and get “You’re posting comments too quickly”, please try again. Sorry for the inconvenience.
Details, for the curious: we’re running this site behind a load balancer, and WordPress’s commenting system doesn’t realize it, so it thinks that everything it seems is coming from the same address.
We have a potential fix and just need to test it and put it into place.
Update: Chris applied a patch we think should fix the problem. If you’re still seeing it, please tell us. Thanks!