As an example (and to toot my own horn), my shared whiteboard tool http://awwapp.com/ is often used by remote-working teams to quickly sketch something. Users could just as easily fire up a drawing program and email the picture, but having the instant feedback makes all the difference.
It's obviously a chat-room for immediate talking, but the highlighting and ease of scrollback (without having to have irssi or similar running constantly) mean you can easily catch up and pick out messages left for you when you were offline.
Which makes me think the post is just about the upcoming book.
We have standups and occasional pairing done remotely (via tmux/wemux). We've been doing this for at least a year and a half now.
Seems like DHH is late to the party. What he says are currently competitive advantages for the companies that already practice it. But I suppose, the bulk of workplaces still have yet to try this out.