"Drupal’s advantages for running enterprise websites are well established by such companies as FedEx, The Economist, and The White House. But many who would like to use it hesitate because they fear loss of assets now managed by their current site’s platform, or expect the procedure to transfer those assets to be prohibitively difficult.
This paper examines scenarios for migrating from other content-management systems (CMSes) and web applications, such as Vignette, Jive, FatWire, ColdFusion, and Joomla. It evaluates reasons for migration, describes migration methods and tools, and suggests best practices. (...)
Websites become harder to maintain as they age. First, evolving web trends demand capabilities that older technologies don’t have. Second, enterprise data and site structure become messy, calling for a reorganization. Third, business factors (such as the availability of qualified consultants) may make the legacy system uneconomic to maintain."