I am looking for examples of web applications or site that use
hierarchical tags or nested tags. For example, I've found that
delicious.com has "tag bundles" which lets the user group related
tags and see all items tagged with anything in that bundle.
Are there other examples you know of that let the user build and use
tags within tags?
I'm currently working on a redesign on an application that creates
threads of emails and related information. I was wondering if anyone
knows of really good examples beyond google mail and the threading in