It has been possible since earlier EADitor betas to use the Flickr APIs to pull thumbnail and reference-sized images given the photograph's URI. If we can use EADitor to create excellent metadata utilizing linked open data web services from Geonames, Pleiades, VIAF, LCSH, and, soon, the Getty thesauri, why not push these metadata back into Flickr itself with machine tags? Libraries, archives, and museums have for years uploaded historical photographs to Flickr, but meaningful metadata are typically lacking. Flickr is regarded as a "cool" thing to do, but the service itself is underutilized as an aggregation engine. What if we took Flickr more seriously as a repository for open content?
Institutions large and small have uploaded photographic collections to Flickr. But what if you want to see all photos relating to baseball in Flickr Commons? Or what if you want to see all photographs taken in Chicago? You can't unless the textual metadata for the images contain your search keywords.
But, as usual, the Pleiades Project is ahead of the curve. As Sean Gilles detailed here, a growing number of Flickr users have adopted the pleiades namespace and a handful of useful predicates (atteststo, origin, depicts, findspot) to associate their photos with Pleiades places. There are now almost 12,000 photos in the pleiades namespace.
So, suppose you have an archaeological archive. You've already used EADitor to associate your manuscripts and photographs to Pleiades URIs. Now, if you're using Flickr as your archive's photo repository, you can inject these IDs back into your image metadata in the form of machine tags. EADitor now communicates with Flickr's OAuth authentication to allow you to log in as a Flickr user, enabling EADitor to use the setTags API.
The interface is quite simple. After you have associated a Flickr image URI to your Digital Archival Object Group (daogrp element in EAD), you can click on the "+Tags" XForms trigger to load a window which contains potential machine tags from your daogrp's nearest parent component. The predicates are bound to drop-down menus that can be specified in your EADitor config. You can also add custom tags.
Once you click the Apply Tags button, the tags will be pushed to Flickr, and will then be available through the Pleiades interface shortly thereafter.
Flickr provides a lower barrier to entry than, say, the Pelagios Project, since individual users who are unattached to digital humanities projects or organizations can link their photos to Pleiades. I think there's enormous potential in machine tagging. Sure, access to imagery is broadened when the Pelagios web page for an ancient place links back to the machine tag search results page on Flickr, but what if you can develop a machine tag system for specific pieces of artwork? Perhaps it might be possible to crowdsource photographs of museum objects which can be fed into photogrammetry software for the creation and dissemination of open 3D models of statues, vases, or other such artifacts.