Brief resume about UserDatas?

Hi Everybody,

I am looking for a brief resume about “user Datas”. You can attach new properties to objects with the “Objects user datas”, like I class you have previously developed. At the same time can you write the same instance of this class into the “Document User Datas”?
If yes, sometimes it is completely open to write in the “Object user datas” or in the “Document user Datas”?

You might start here:

– Dale