PHP is a popular programming language. Much of the web is running on it, and many Open Source projects use it. This is because PHP is a very easy language to use. Everything about the language is designed to make life easier for the developer. It lets you make quick applications without having to sweat about syntax, or compiler errors. For an inexperienced developer, or a small project, this is great. If you have to maintain the code, however, this can cause problems.