This creates a web server using Apache with PHP and MySQL database. Apache is a well known and popular web server with extensive documentation. The other web server that you may consider is Nginx, which operates in a different way to Apache in that Nginx is event driven and for systems that have low resources such as a RaspberryPi, it could give better results.
However, I have used Nginx on my previous Raspberry Pi web server and although it worked well I have found I can understand Apache better than Nginx particularly when it comes to configuration. The latest RaspberryPi is much more powerful than the first version and providing you do not receive too much traffic there should not be an issue.
The Raspberry Pi is an interesting project to create a web server which may be used for a small web site or for testing purposes. It enables you to become familiar in working with the Debian Operating System, the command line interface and aspects of installing packages. It also enables you to work with a Firewall and then connect it to your own router so that it can be viewed from the outside world.