What's an Entity System?
(or "Component-Oriented", or "Component-Entity System", or "Entity/Component System")
Entity Systems (ES) are a technique/architecture for building complex extensible projects (mostly: computer games) based around pluggable behaviours and lean, fast, modular data.
This makes the programming process leaner and easier to extend, with advantages in: performance, extensibility, and game-design flexibility
You can build anything you want and call it an Entity System, there are many approaches, but some have proved more effective/practical than others. This site tries to cover all the approaches which people have used/are using in live games. We cover everything from simple theoretical examples (e.g. RDBMS with code in systems) through to popular open-source frameworks (e.g. Artemis Entity System Framework)