The company said that offering more services over the web was easier with Server 2008, which it described as "more stable" than the 2003 package.
The move to Server 2008 was part of an IT refresh that also involved new hardware and a new hosting provider.
Reed technical director Mark Ridley said many of the features on the site that were previously only available to signed-up customers would soon be available to everyone.
One of the benefits of the new system was better integration with in-house development code. Ridley said, "We use .Net in-house for development, and with Server 2008, there is tighter integration between the code we are writing and the server itself."
Ridley said the biggest IT challenge was finding enough time to test the new servers. Preparation was made easier by using the old Windows Server 2003 servers at the same time. The company continued to run the old servers as it was preparing to use the new system, which went live in November last year.
Reed also used testing software from Scivisum to help develop real-world examples of how users would use the site.
Ridley said, "The 2008 servers don't really change the way the website works. They just give us more answers to the problems that we face. With Windows Server 2003 we were relying on not particularly stable third-party components and we really wanted to replace those."