acts as taggable worth using?

This should help answer your question:

Welcome to FlickrCentral!  Just like Grand Central but without the oyster bar, the trains, New York city...  FlickrCentral is a place for the newbies to get a taste of what Flickr is about, and a place for the more experienced users to keep a finger...

The fundamental point is that you let your users do the organization and categorization of the content. Usually it's them tagging content they themselves have created, but it's not unheard of to allow users to tag content created by others (such as visitors tagging content /you/ create).