adding an A record with our new address: 209.20.70.130
Wouldn't a CNAME be a better idea?
I've noticed this in a bunch of places, weebly, tumbler, heroku: Why aren't this done using CNAMEs for exactly this reason? Also, it'd give them more freedom over their infrastructure, would be able to separate it on different datacenters etc.
Ah, the answer is in the comments. A root-domain can't be CNAME, so to avoid confusion they just tell people to use A.
My DNS provider has a web-forward service, though, so I can translate domain.tld to www.domain.tld before even hitting my server.
They should be providing both as an option. There are a lot of people who use sub-domains, and in that case a CNAME is a better option.
I was still impacted by this yesterday and was surprised they couldn't mitigate the attack better. I like Posterous as a platform but am concerned about keeping my stuff there at this point.