Hi Blessing,
I’ll reply as Stefano for sure is tired from the trip 
I copied the email to the GeoNetwork user list as the questions are relevant to a broader community.
See below:
On May 23, 2006, at 1:19 PM, Blessing Siwela wrote:
Mirko, Stefano,
Hope you guys travelled well.
We are trying to do a bit of customising of our Geonetwork node (and its going well).
Good!
However, I have a small question regarding the addition of new ‘Categories’. I have seen that there is a facility for adding new categories when you login as administrator. I have used this to create a couple of categories. The question is, when you add metadata records, how does the metadata record get associated with these new categories, which are not part of the ISO19115 standard?
While logged in as editor, you will see a separate button with the metadata, next to the Edit and Privileges buttons named Categories. Click on that one and select the categories you would like to be associated.
Also, my new categories are being displayed in braces , unlike the ones already in.
The non-localized strings are displayed in brackets. To make sure the categories are localized, you need to add them to the localized strings.xml files manually. These files are in the …/web/loc/…/xml/ folders (one for each language).
While categories are nice, they are purely local and will not be reflected by other GeoNetwork nodes displaying your data. This allows you to locally do some “content moderation”. However, I’m not sure how categories will be used in the future versions. For vesion 2.1 it will for sure still be there. In later versions that will depend on what users would like to see
Ciao,
Jeroen
Have a good day.
Regards,
Blessing