The Doctrine Common annotations library was born from a need in the Doctrine2 ORM to allow the mapping information to be specified as metadata embedded in the class files, on properties and methods. The library is independent and can be used in your own libraries to implement doc block annotations.
Annotations is introduced by modern programming languages like C# and Java 1.5 Tiger as new and convenient feature. It is rather new innovation in PHP, many Java users are using it for a long time already for auto-generating source code, configuration files for different frameworks and so on. phpannotations provide you with similar features like xDoclet does, that is all ...