Tagging uploaded files

[SamWM]

I think it would be useful if you could tag files after you have uploaded. If that functionality existed, it would be easy to create a component/plugin/template that could list files matching a given tag. e.g. get_files() (all files) / get_files('tag-name') - returning array of files (including file size and created/last modified too maybe).

I cannot see how you could do it as a plugin - I can see the files-uploaded and files-extra hooks, but not sure how these could be used to extend the files feature.

Also the 'hello world' sample plugin does not work as is Call to undefined function add_hook()
I've found that this is the case with the latest version and 2.0.1 - it should say add_action instead.