If you go to the bottom of the page at http://allthingsdistributed.com/, you'll see that the blog actually requires "Movable Type Pro".
AWS doesn't provide a way to serve from S3 without the help of a CNAME redirect, which means that you're out of luck if you want to use the Jekyll+S3 setup with a naked domain name (naked, as in no "www" or "blog" subdomain). And it also means that you're going to have to get some other server (Google Apps can do it), to redirect your *.domain.com queries to www.domain.com. And then your users' DNS is running all over the place, incurring, in my opinion, unneeded delay.
Actually that was my fault. I had just switched off the redirect of allthingsdistributed.com to www.allthingsdistributed.com and as such you ended up at the old MT installation. That is now corrected.
You are correct; to map to an S3 bucket you need a CNAME. But DNS doesn't allow the apex to be a CNAME so you will need to redirect that. Route53 solves that for EC2 with the help of ELB. But there is no such solution for S3 (yet).
I am using the www subdomain as much as possible, so the redirect only happens if a visitor actually types in the apex name, in all other cases they will get where they need to be directly. But I agree that it would be better to solve this at a different level.
AWS doesn't provide a way to serve from S3 without the help of a CNAME redirect, which means that you're out of luck if you want to use the Jekyll+S3 setup with a naked domain name (naked, as in no "www" or "blog" subdomain). And it also means that you're going to have to get some other server (Google Apps can do it), to redirect your *.domain.com queries to www.domain.com. And then your users' DNS is running all over the place, incurring, in my opinion, unneeded delay.