There are both open-source, free Web Application Frameworks and commercial, proprietary frameworks. The latter is more expensive, but it will generally come with more support. Web Application Frameworks usually focus on a specific language. Django works with Python. Additionally, every Web Application Framework has its own level of complexity and learning curve, documentation, and support. Most web developers will want a Web Application Framework in a language they are fluent in. A solid library of extensions and plug-ins is also ideal as it reduces the amount of work the developer will need to do. Since the Web Application Framework has a lot to do with how a system functions, the system's look-and-feel may also come into play, as may other quality of life issues such as the robustness of the administrative panel.