Books at the CCEL are stored in Theological Markup Language, an XML application designed to support the needs of digital libraries and electronic texts, especially for Biblical and Biblical-related literature. ThML has been adopted or supported by a handful of other projects. Books are converted into end-user formats such as Web pages and PDF files by XSLT stylesheets and other methods.
The Web site is based on the drupal content management system, with lots of our own code as well. Currently we are running a load balancer and three servers. This enables us to support almost all traffic peaks, which occasionally reach 20 page views per second.
As of August 2006, we were serving around 200,000 page views a day from about 600,000 different users a month, and we send about 2000 GB of data per month, or the equivalent of about 2 million books.
A few tech reports are available.