The rubygems.org infrastructure has been under heavier and heavier load and the need to move to something that handles the load better was well established.
On October 3rd, I opted to begin the migration to a setup based on RackSpace Cloud I had been working on for the last few weeks. This setup uses different instances for load balancers, application servers, and database and is designed to be able to deal better with the load that rubygems.org generates.
Upon coordinating with other developers in #rubygems on irc.freenode.net, at 13:56 PT we (the rest of the rubygems.org team) were all happy with the new setup and begin the transition.