Quoting Dan Karran <dan@karran.net>:

> Does anyone know of a way currently to add your own tags to other people's
> content within a Drupal site? I know of the community tags module, but I'm
> looking for a way for people to be able to organise content within a site
> according to their own taxonomies, instead of a shared taxonomy that anyone
> can edit.
>
> Any pointers appreciated.
>

Nice idea. Maybe some of the many taxonomy modules could help. Using
the browser client window and searching for taxonomy on
http://drupal.org/project/Modules/name might give you hints.

Thanks for the pointer Earnie ;) I'd tried some different combinations on Google with site:drupal.org but it didn't throw much back at me that sounded like what I was looking for.

There sure are a lot of taxonomy related modules, and after quite a few taps of the enter key searching through the module list, it sounds like Taxonomy User module might be what I'm looking for, and it's being merged with Community Tags for D6.