I have run across a couple of of systems that allow you to organize items by marking them with arbitrary tags instead of imposing a hierarchical structure. WordPress and del.icio.us both do things this way. I hear tha GMail has this type of tagging too. See a message in the [delicious-discuss] mailing list for reasons why del.icio.us uses tags.
This flexibility is nice when doing ad-hoc activities like writing blog entries or saving bookmarks. It takes some up front work to get the hierarchies right. On the flip side, I think its a little harder to navigate around once there are a lot of entries.
Right now I’m trying out a hybrid approach for categories on this blog. For example, I tagged my last entry about using WordPress with both “Tech” and “Blogging”. “Blogging” is more specific then “Tech” so it could be seen as a sub-category.
I’m hoping this approach will this will allow me to organize things better in the future. For example when you click on the “Tech” archive link, it would be nice if it gives you all the sub-categories of “Tech”, instead of just showing everything. Of course to do this I need to make the super/sub category relationships explicit.
One problem with this approach is that if something gets categorized as “Blogging” but not “Tech”, what does that mean? One solution would be to automatically tag something with all super-categories when you tag it with a sub-category.
>>Update: I upgraded to WordPress 1.2 and discovered they do have super/sub category relationships now. I’ll be experimenting with them.