Hi Nehal,
These properties represent how the user wants to be nottified of new announcements of a certain category. Announcements are created over the "Announcements" portlet.
If the user, for example, checks the email checkboxes he wil receive an email when a new announcement of this category is created in a site the user is a site member of. Of course, for successfully sending emails the outgoing SMTP settings needs to be correctly configured over Server Administration -->Mail.
Regards,
Kim
