Web pages, and especially weblogs, include apparently unnecessary links all the time. For example, is there really any need to link to Microsoft every time I mention the company’s name? Is anyone reading this posting going to follow the link (and if so, would that person have had trouble finding the site otherwise)?

Hub and Spoke

The best term I can think of to describe these links is hub URLs. They’re very much like airport hubs — connections from many smaller places feed into them, and often the only way to get from one small place to another is by passing through the hub as an intermediate point: for example, if I link to Microsoft and you link to Microsoft, someone can trace a route from my web page to your web page by changing planes, so to speak, at the Microsoft hub. One way to make the trip is to put http://www.microsoft.com/ into Technorati or a similar search engine that can supply ongoing results in an RSS or Atom feed, then read the postings that congregate around this hub URL in the blogsphere. The weblog postings are not linking to Microsoft so that you can find Microsoft; they’re linking to Microsoft so that you can find them. The nature of a hub URL is that the spoke web sites need it more than it needs any one of the spokes.

To take a less hackneyed example, here is a Technorati RSS feed of all weblog postings that link to Roy Fielding’s famous dissertation on web architecture. Granted, that’s not a very active hub URL, but still, all of the postings that link there form a community of interest, and a RESTafarian will almost certainly want to subscribe to such a feed. I expect that, more and more, the blogsphere will start grouping itself around hub URLs at least as much as it groups itself around individual personalities today.

Travel agencies

So far, so good. Search engines, the travel agencies of the web and blogsphere, already know how to take advantage of these hub URLs, as in the Technorati example I just cited above. Unofficial rumour has it that Google, for example (there I go again with a hub URL), makes great use of hub URLs for determining the relevance of search results. In fact, the whole push towards tags and folksonomies by sites like Technorati, Flickr, and del.icio.us is really an attempt to set up their own hub URLs.

In Technorati’s case, the travel agent wants not only to plan trips but to own the airport hub itself: that’s why they’re encouraging bloggers to link to the tags section of their site, making URLs like http://www.technorati.com/tags/web into hub URLs that are entirely under their control; it does not seem likely that their competitors will go along with that idea, though.

Castles and Boroughs

On problem is that the most popular URLs might end up becoming not only hubs but castles. Castles are cute tourist attractions today, associated mainly with pseudo-medieval romantic kitsch like knights and tournaments, but in the Middle Ages they were often instruments of oppression. While free landowners may originally have congregated around them for protection, they often lost their freedom (either by choice or coersion) and became feudal serfs, little more than the property of the powerful thugs who controlled the castles. If we start building our weblogs and sites in clusters around powerful hub URLs the way that free peasants built their huts around castles, are we risking the same fate?

Castles don’t show up automatically whenever people congregate together, of course. The alternative is the borough. Most of us in the developed world crowd together in suburbs, towns or cities, the ideological descendants of the boroughs, so that we can share services like water, electricity, roads, and shopping. While we have to make some compromises to live in close proximity, we do not have to give up fundamental freedoms the way that serfs around a castle did. The reason for that is that most economically-advanced countries have cities that are governed democratically rather than by a single strongman like a feudal lord; even in the Western European Middle Ages, boroughs enjoyed many freedoms and privileges, and were at least partly self-governing. So, getting back to the blogsphere, the question is this: do we want our hub URLs to be more like castles or boroughs?

This is an important question, because it is not farfetched to suggest that the owners of the most popular hub URLs could eventually start limiting the rights of the sites or blog entries linking to them. The entertainment industry has already had great success shutting down Bittorrent trackers, which simply link to files rather than actually hosting them; several courts have issued rulings against deep linking, like this one in Munich in 2002. Even when specific rulings are later overturned, it should be clear that linking is not off limits for legal action, and it is not impossible to imagine a future where someone has to agree to restrictive terms of service or even pay for the right to link to a popular hub URL like a Technorati tag or the Microsoft web site.

Wikipedia-boro

I have already suggested that Wikipedia would be a good source of subject codes, and in essence, that means using Wikipedia URLs as hub URLs. Wikipedia is not the only choice, of course, but it seems to be a particularly good one for a few reasons:

1. it is a collaborative site where anyone can add new potential hub URLs and modify the information in the pages they point to
2. our rights to use it now and in the future are guaranteed by the Gnu Free Documentation License (though to be strictly pedantic, that applies to the content rather than the URL itself)
3. linking to the Wikipedia is more likely to give you a fair description of a subject than linking the subject’s own website (think of the difference between a politician’s own web site and the Wikipedia article on the politican, and you’ll see what I mean)

If enough people start linking to Wikipedia articles in their weblog postings, topic-based RSS or Atom feeds will become very easy: for example, Feedster will happily give you an RSS feed of weblog postings linking to the current U.S. President Bush or a feed with postings that explicitly link to the country Canada: presumably, these articles are treating these topics as major subjects, rather than just mentioning them in passing, so the contents of the search feeds should be highly relevant (imagine how many false hits you’d get from mailing address, etc., just searching for the word “Canada”).