Tag Clouds are a common feature of websites based on "folksonomies". At a glance, a casual viewer can see not only what interests that author, but the intensity of that interest. Take, for example, the following tag cloud from an anonymous Flickr user:
The size of the font indicates the number of times that tag has been used, and to some extent the level of said person’s interest in that subject. Here we see that this guy uses his Nikon D70 quite a bit, and takes lots of shots of someone named "Mabel." This is most likely a member of his family, since that word also appears in large print.
Geotagging makes use of three tags – one for latitude, one for longitude, and one to indicate that the item has been tagged, as follows:
The first tag is general, and places the item within the overall global category of things geotagged. The other two are specific to that item itself. Triple tagging need not be limited to geotagging. Geobloggers.com gives examples of how other triple tags could be generated.
Anyone can follow this [namespace]:[key]=[value] convention. If I wanted to sell my bike, I may add a photo of it to Flickr and add the tags:
There’s the declarative tag and two TripleTags. If it gained traction and enough people did it, then it’s easy enough to build a website or services that handle the searching and tagging of photos of items people want to sell.
The problem with this is that your tag cloud quickly becomes cluttered with lots of triple tags that are specific to one item, and one item only from your collection of items. This tends to defeat the purpose of a tag cloud, which is meant to cluster items that are related. Take, for example, my tag cloud from my Flickr account:
The terms "southcarolina", "greenville", and "nikon" still leap out, but the middle of the cloud starting say, oh, around the letter "g", looks like unintelligible gobbly-gook.
This points out a basic incompatibility between triple-tagging and folksonomies. Tags are created by humans and meant to be read and used by humans for organization. Triple tags are meant to be parsed by various pieces of hardware and software so that, in the case of geotagging, the item can be displayed on a map.
There are efforts underway to reduce cloud clutter. In the case of geotagging digital photographs, one could make sure that the geodata is included in the EXIF data for the image. However, if the photo is scanned from a film copy, or is manipulated with HDR or some other technique, there is no EXIF data, and the photo must be manually triple tagged. Flickr is examining ways in which the geocoding is somehow separated from the cloud so that it still appears, but doesn’t create clutter. I hope they are able to come up with a solution soon, because I don’t intend to stop geotagging my shots.
[tags]geotagging, EXIF, Flickr, Triple Tags[/tags]