DHH points out the way their app was configured it was never really going to scale anyway, and that they certainly could improve their performance with more caching and more database servers. He does end on a sort of Rails is open source, you can always fix it yourself note, which is a little disingenuine.
Brian McCallister responds to the whole thing with I think the best perspective of all.
Update: Problem solved. (Dr Nic to the rescue.)
Update: And again. (This looks really promising.)
Update: And again. (Dr Nic again — he’s good.)