Flickr Machine Tags

Flickr recently announced a new feature called "machine tags". From their announcement:

"Machine tags" is the technical term for the extra hamsters we've added to the Flickr servers to formalize how these sorts of tags are treated. I've included a "Ceci n'est pas un FAQ" below with all the details.

Machine tags follow a lightweight format:

namespace:predice=value

The namespace defines a class or a facet that a tag belongs to ('geo', 'flickr', etc.) The predicate is name of the property for a namespace ('latitude', 'user', etc.) The value is, well, the value.

Like tags, there are no rules for machine tags beyond the syntax to specify the parts of a machine tag

Tags that follow this format are automatically grouped under "machine tags" in the Flickr user interface, and can be hidden or shown by the user.

Machine tags, while not having a name, have been around for a while, their usage driven by people's urge to organize tags and give them specific semantics - and then, to build applications on top of this, assuming this specific semantics. I've discussed this a while ago, when I was younger. Back then, I suggested the name "applitags" for this feature, and suggested a slightly different format for differentiating Machine Tags (or applitags) from People Tags:

x:namespace.tag[=value]

I do wish the Flickr folks would have gone a step further and formalized the namespacing issue as well, as this would have made software built on top of Machine Tags more reliable. Still, this is an important move, coming from one of the tags-trend-setting players.

Are we re-building XML from the ground up all over again though?

Technorati Tags: flickr Machine+Tags applitags XML tagging

applitags

As the usage of tags increases, we see more and more "applitags" (there I go again…) – tags that have a specific applicative meaning. Sometimes there is an actual application generating and / or consuming them (e.g. geotagging), or there is an application whose logic is run, at least as of now, by people – manually.

An example of the second kind of applitags is the Deleteme and the 1-5-favorites groups in Flickr. In both, there are guidelines instructing users which specific tags to add or remove under what conditions, and what actions to take as a result. Users actually follow these (somewhat complex) guidelines, since they are essential for maintaining the goal of the groups.

Usage and definition of applitags is somewhat of a wild west thing at the moment. Rules are defined ad-hoc, and are implemented by the users themselves – manually.

It would be good to standardize the format of these tags, to differentiate them from the free-association user tags, in order to reduce the chance of a user changing these tags and breaking a future application that is leveraging these tags.

Here is a proposed definition for applitags:

Applitags are tags whose spelling and semantics are agreed on between a group of users, or between users and a producing or consuming application.

Generic format for applitags:

x:namespace.tag[=value]

Example:

x:geo.geotagged
x:geo.lat= 31.70
x:geo.lon= 35.20

x:deleteme=1

The purpose of the "x:" is to distinguish applitags from normal users tags, to hint to users (and later, to tag editing applications) that these tags should not be modified without knowing the rules governing them (or better yet, outside an application designed to product them).

There are different types of applitags, but more on that later.