Making Tagging More Useful

Posted 30 December 2006

Tagging has become one of the themes of so-called Web 2.0 sites. Really nothing more than free-form keywording, tagging has proven useful in many contexts. Eschewing hierarchies and controlled vocabularies, tagging reduces keywording to its essence. For many of my uses, though, I’ve been finding it it just a bit too simple.

Tag clouds

Seven years ago, the startup I led (Fotiva) built one of the first photo organizers to use tags, which Adobe brought to market as Photoshop Album. Since then, tags have become a popular organizing method on the web, not only for photos (most notably at Flickr) but also for web bookmarks (such as at del.icio.us) and for blog posts (encouraged in large part by Technorati). Rather than offering any tag hierarchy, typical usage on the web is for all tags on a site (or within a user’s account, for private tags) to simply exist in one big namespace, sorted for display either alphabetically or by popularity. A hybrid listing, sorted alphabetically with type size denoting popularity, has become known as a “tag cloud”.

Hierarchical tags

For me, this approach doesn’t scale well. With more than a few dozen tags, the organization cries out for some further structure. This is true for tags describing web pages as well as tags describing photos or blog posts, but the sheer number of photos I take, and the diversity of their tags, first made the problem acute in that context. I have tags for a dozen different types of boats, for example, and for several dozen places, and for more than 30 people; mixing those together in an alphabetical sequence is counterproductive, yet that is what sites such as Flickr force you to do. In the Photoshop Elements organizer (which is where the Fotiva/Photoshop Album code base ended up), you can have hierarchical tag categories, so I have Places > USA > California > San Francisco Bay > Angel Island, and Boats > Sailboats > Schooners. I have hundreds of tags, and without these categories they would be much harder to use.

A proposal for tag clusters

To use the tag hierarchy in this way, you have to create tags within the hierarchy. Once tags are created, you can apply them in Photoshop Elements using drag-and-drop from the tree-structured tag list.

Simply entering tags as free-text, whether they are new tags or ones you’ve used before, is widely used on the web, and it is the ultimate in simplicity. But it doesn’t provide any clear way to support a tag hierarchy. With a few dozen tags, it’s fine, but as time progresses and you have more tagged material, it becomes less effective.

For blog authors, the problem is similar but has some different twists. For this blog, I have sections and tags, but they have no relationship to one another; they are two orthogonal organizing schemes. Sections are more static than tags; they must be created independently of creating a post. Tags, on the other hand, can be freely created just by entering them when creating a post. Since blog search engines such as Technorati, as well as some photo sites like Flickr, search on the tags, it is important to have reasonably specific tags, especially if you want to associate blog posts or photos with a particular event.

So what I end up with is tags that are very specific, and sections that are very general, but no connection between them. If tags knew what sections they belonged in, then I could dispense with assigning posts to sections as well as giving them tags. I could also list the appropriate tags as an index for a given section, to provide an easier way to navigate it.

Ideally, sections should be created by clusters of tags. For example, posts tagged as ruby-on-rails or php or css should all appear in the Web Development category. The question then becomes how tags get associated with sections. Any time a new tag is used, the blog engine could prompt the user for the section to which it belongs. Potentially, sections could be inferred automatically, using an existing lexicon for reference.

I think a similar approach could work for tagging photos. It could make sites like Flickr more capable organizers, or make programs like Photoshop Elements easier to use for tagging.