Building a complex, high traffic, Drupal site from scratch is challenging. Converting a site that already has a high traffic web presence to Drupal while maintaining the legacy site throughout the process is like changing your tires at 60 MPH. Martha Stewart Living Omnimedia tackled this very issue on an enterprise scale, running two CMS systems, Vignette and Drupal, simultaneously under the same domains. While the new site was being built, the legacy site was still being maintained and updated, the Drupal development environment was continuously updated with fresh data from the legacy site, and users were intelligently routed between pages from the old and new sites. New features were rolled out iteratively and a third internal Drupal installation, the "Enterprise Content Library" played the role of a canonical location for all content, while maintaing the integrity of all MSLO's myriad assets. If that wasn't already challenging enough, the MSLO site was deployed in Drupal 6 because it required modules not yet available for Drupal 7, but it also needed some functionality only available in Drupal 7 to be able to manage tens of thousands of user accounts and provide rich, fieldable comments. The solution was to create a separate Drupal 7 environment for users and comments and configuring it as a central repository for the user-facing sites. This not only accomplished the goal at hand, but offered the added benefit of diverting a lot of activity away from the main site. Join us to find out how we tackled these and other issues while the new site components were built, transitioned and eventually launched in an iterative fashion. We will discuss Drupal 6 and Drupal 7 modules we used as well as tools and resources provided by Akamai and Varnish. At the end of the session, users should gain a good understanding of how we managed to run existing websites while simultaneously building out a new platform. These issues will be presented both from a technological perspective as well as a general project and program management perspective. This session will be co-presented by Lullabot James Sansbury (q0rban) and the MSLO Internet Technology team.