Drummond Reed picks up the thread I have been raveling (or unraveling?) about open tagging, and demonstrates a solution to the use of absolute and relative URLs that I outlined in Open Tags: Made For A Distributed World, based on the XRI proposed standard (which I confess, I was blithely unaware of until this moment):

[from Open Tagging]

So what's the XRI solution? Switch from an HTTP URI to an identifier syntax specifically developed for abstract identifiers (including generic concepts like "+Thai" that don't exist as definitive HTTP URI resources). For example, the XRI-based open tag would look like this:

<a href="xri:// thai" rel="tag">Thai</a>

What's the "+" stand for? It's the XRI global context symbol for generic identifiers - identifiers that represent generic subjects, topics, or concepts for which there is no central authority, any more than there is any one authoritative dictionary for the meaning of the word "Thai" in the English language.

So how would an XRI-aware browser (or search engine) deal with this tag? Exactly the way Stowe intends. Because the author of the tag did not put "+Thai" in the context of any specific dictionary service, the instruction to all service providers is: "interpret this tag as the generic meaning of the concept 'Thai'." Each service provider can then consult their own dictionary service to provide further understanding/mapping/linking of this term. Or they can use a shared community dictionary service from organizations like Wikipedia or XDI.ORG.

Better still, XRI syntax allows an author to declare a explicit dictionary authority for a word if they choose to. For example...

<a href="xri://technorati.com/( thai)" rel="tag">Thai</a>

...would tell interpreters of this tag that the author is referring to the generic concept of "Thai" in the specific context of the dictionary provided by the authority "technorati.com". The author can cite any authority they want, including themselves. For example, the following two examples would be two different ways of citing myself as the dictionary authority (the first using a DNS domain name address and the second an XRI i-name address):

<a href="xri://equalsdrummond.name/( thai)" rel="tag">Thai</a>
<a href="xri://=drummond/( thai)" rel="tag">Thai</a>

Finally, to provide backwards-compatability with existing HTTP URI infrastructure (i.e., until the XRI scheme is understood natively by browsers), any XRI can be transformed into an HTTP URI using an XRI proxy resolver such as the one publicly available at XDI.ORG. For example, the second XRI above could be turned into a "clickable" link today using this proxy resolver by expressing it as:

<a href="http://public.xdi.org/=drummond/( thai)" rel="tag">Thai</a>

There are even more features that XRI brings to the complex problems of tags, ontologies, and shared meaning (especially the concept of synonyms, for establishing equivalence of concepts across communities and even across human languages), but that's enough for one post. The best part is that XRI syntax is quite mature. The OASIS XRI TC is preparing the second Committee Draft of the XRI 2.0 specs right now for a full OASIS vote this fall. Identity Commons has already started to i-name enable WordPress. Since no registration authority is required for the XRI space, open tagging with XRIs could start happening organically as fast as taggers decide to start using it.

I haven't started to dig into the XRI spec, but I intend to. However, the assertion that we can start merrily open tagging (tra la) with XRIs fails one critical test: I would like to have taggregators like Technorati accept these tags as equivalent to the closed URL-based tags currently in use. Without that major shift in the tag ecology, XRIs have a long road before migrating into general use.

[PS I glanced at Drummond's first post, and discovered that it was Doc Searls that convinced him to start blogging as part of the whole XRI standard push. Why am I not surprised?]