DAM, DAM with Digikam. Public vs Private metadata.

Dear all,

The Digikam documentation here:  http://docs.kde.org/development/en/extragear-graphics/digikam/dam.html

talks about the difference between public and private metadata.  Specifically, it says:

"One distinction has to be interjected here between private and public metadata. One could say that all file-embedded attributes are potentially public since the images may be exported, sold, and copied to other places and people. On the other hand all non-embedded metadata in the database can be considered private as they stay in the database and go nowhere else. By adjusting digiKam's settings accordingly you can control what kind of data remains private and what will be embedded and eventually become public."

I'm struggling to find out how to specifically understand what is public, and what is private in Digikam, and how to toggle between them (so, for example, how to easily define what I want pushed and written to the file etc).

Where are the settings in Digikam that allow me to specifically choose to embed metadata to the file - metadata item by item - so that I have real control over what is written to the file and what isn't?  And suppose that I include all this data in my files as part of my normal 'internal' system - but then want to remove and scrub some more personal or irrelevant metadata from a photo before publishing a version to the web, how would I go about that?

Is there a simplified system that allows me to 'uncheck' metadata items before exporting a final version of that file, so that they are not carried forward?

How would I achieve that?

Thanks in advance.

Mark.