Running a website which attracts large numbers of vistors and which generates large numbers of data throughput takes more than a simple standard Apache webserver running on a standard Linux box. When you expect large numbers of visitors which you have to serve 24 hours a day 7 days a week you will have to think about network architecture, failover clustering, scaling your machines and what system should be behind your website, Apache or something else.
Oracle Application Server, more known for running Oracle E-business suite in most cases can also be used to run a website. Oracle Application Server 10g is developed with a demanding 24*7 environment in mind and copes with all the questions like "can I use grid computing" or "what about backup servers". I never experienced the power of Oracle Application Server as a web platform for consumer intended content and graphical rich websites until recently I was involved in the setup of a high availability website for a Dutch TV program named "the taste of life". This website is developed with some partners by SmartApps who are also providing the hosting of the Oracle Application Server.
When developing a high availability web platform you might want to take a look into Oracle Application Server.