Flickr Introduces Machine Tags

Flickr is one the most popular mashup platforms: as of today there are 159 Flickr mashups listed here. Now, Flickr made some very interesting enhancements to their service and API this week when they announced Machine Tags.

What are they and how do they relate to the API? From the announcement:

# What are machine tags?

Machine tags are tags that use a special syntax to define extra information about a tag. Many of you may already be familiar with machine tags by another name (triple tags) or because you are already using them, informally, in your code (for example, "geo:long=123.456"). Like tags, there are no rules for machine tags beyond the syntax to specify the parts of a machine tag.

Flickr has already used machine tags, informally, on a couple of occasions : When we launched Maps, we provided a way for people who had "geotagged" their photos to import their location data. This was done using the "geo:lat=..." and "geo:lon=..." tags. When a user tags an event with an upcoming ID (for example : "upcoming:event=81334") we display a link back to the

# How do I query machine tags?

Via the API!

Specifically, using the "machinetags" parameter in the '' method. Like tags, you can specify multiple machine tags as a comma separated list.

# Can I query the various part of a machine tag?

* Find photos using the 'dc' namespace :

{"machine_tags" => "dc:"}

In some ways it's a small announcement but yet it's another very useful step in adding structure and meaning to the ad-hoc user-defined parts of the web. And it certainly creates some interesting mashup possibilities.

Be sure to read the next Photos article: 200 Photo Mashups