To be more specific, it’s been added to the domain mapping extra for WordPress.com. Domain mapping is the reason you see this blog as changingway.org, rather than as changingway.wordpress.com (which it also is). It’s also the reason you can email me (as andrew) at changingway.org.
With the addition of DNS editing, domain mapping is also the reason you can see other outposts of the changingway.org empire. Or rather, it would be if there were such outposts. Right now there aren’t: there’s just blog and email.
Andy Skelton, posting for Automattic, explains DNS editing as follows. “The ability to add some common DNS records (MX, TXT, CNAME, A) opens the door for services hosted elsewhere to work under the same domain as your blog.” He uses the examples of email (already available, but I think that DNS editing makes it more flexibly available) and wikis.
Another aspect of Andy’s explanation is interesting: “we tired of saying “no” to users wanting email on their blog domains so we added limited support for Google-hosted email… we tired of saying “no” to users wanting DNS control so today we deployed a DNS editor.”
So Automattic can get tired of saying no, and enhance a product so that the answer is yes. I’m explicit about this because some seem to doubt that it ever happens.
On the other hand, Automattic will keep on saying no to the “make everything free of charge” requests that seem to follow its every move. Andy refers to DNS editing as a “free enhancement,” and it is – but it’s an enhancement to a premium (as in costs money) feature. DNS editing will make the domain mapping feature more valuable to some.