How to enrich a user profile with personal tags

Hi,
I was looking for a method or a service that returns all the tags attached
to different work items by a specific user within a project area. Is there a
possibility to enrich the user model with such information?
The idea is to develop a server-side component for storing all the tags of
each user similarly to how we can retrieve all tags of each work item. Can I
do this exploiting some existing methods or services or should i query the
database?
Many thanks for your help!

Antonio