I haven't seen this anywhere else yet, so if it already exists as a plugin a pointer would be appreciated.
I want to be able to add arbitrary tags (as in metadata labels, not html tags) to posts, in lieu of the category functionality. Basically, I want each post to have its own del.icio.us style tags. A text box that splits a space-separated list into individual tags is really all it would take. Tags that already existed would just get another post linked to them, while new tags would be created and linked automatically. Furthermore, an RSS feed for each tag would be nice.
I think this could be implemented even within the existing category architecture by making each tag a top-level category (i.e., no children), however there is no current way to easily add new categories at the same time you make a post --it's a separate process. Also, I'm not sure that the existing categories implementation is intended to handle what could be hundreds of top-level entries.
Maybe this is a "custom field" thing -- I don't understand what those are for anyway.
Any ideas? suggestions?