What difference is there between an usual Eclipse project and a Kermeta project ?
Explanation on the difference between an usual Eclipse project and a Kermeta project.
When adding the Kermeta nature to a project, the Kermeta Project Manager (KPM) tool is started which allows you to create rules in order to perform automatic tasks (like transformations or typechecking).
Since kermeta 1.0.0, Eclipse takes advantage of KPM in order to improve project managements like typechecking the files in your projects. Do not forget that you can always add or remove the Kermeta nature from a project at any time (with a right click on the project).
Note that You can extend KPM to perform your own actions. Please contact Kermeta developers if you need more information to do that.