Am Mittwoch, 22. Februar 2006 10:57 schrieb Graham Klyne:

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Hello Graham, thank you for your answer.

I have been using the W3C web site now for many years, and the inconsistencies you mention have never been a problem for me -- indeed, I hadn't even noticed them until you mentioned them.

Why is this? I hypothesize that it is because, when the Web is used effectively, it is really quite rare to enter a URI manually. Instead, one uses various index pages, RSS feeds, search tools and so on to find a URI, and then simply click on it. Many URIs are never seen by human eye, but placed behind descriptive links.

I'm not convinced. Many other people might not notice improper URIs or might not care about them. But I do care! URIs are text and shall be human-readable and human-understandable. (I think, this view is also backed by the W3C.) Normally, every URI can be seen—at least in the browser window. Nowadays, people might have gotten used to cryptic URIs like http://www.amazon.de/exec/obidos/tg/browse/-/301128/028-9225198-9779755? site-redirect=de so that they don't think of a URI as something a human should be able to understand. But I'm sure that this is not what the inventors of URIs (or URLs) had in mind. And users should be provided with URIs which are as easy to remember and as sensible as possible, in my opinion, so that they have the ability to also enter them into their browsers by hand. How often can you see publications on paper which say something like: To learn more, first go to http://www.our-institution.org/, then click on the link "departments", then on the link "our department" and finally on the link "great new project". I think, it is far better to just say: To learn more, go to http://www.our-institution.org/departments/ours/great-new-project In the past, URIs became mostly something that only the computer is expected to deal with, not the human. I'm very much opposed to this and are therefore a fan of nice URIs. ;-)

W3C themselves use URIs very intensively in transient communications, and their mailing system is set up to facilitate this (see their x-archived-at mail headers). A result of this is that the email archives, together with the web site pages, form a tightly interlinked collection of documents and comments that can be, and are, frequently cross-referenced rather than reinvented.

But, for this to work, once a link has been placed in a document, feed, archive or whatever, it is crucially important that it continues to work for as long as the information it references is of interest to people. Without this, all the devices we use to find our way around the web simply fail -- not all at once, but over time. Even with every intent to maintain stability, this happens, but if you allow that URI stability is somehow less important than other conveniences, then I think all hope is lost for information continuing to be accessible.

Of course, stable URIs have a lot of advantages so URI stability is not something that should be ignored. But it should be weighed against other (important) things. I think that URI stability shouldn't always have the final word.

As for the difficulty of designing a consistent URI naming scheme for all time, the W3C position explicitly recognizes this, and this is why they recommend incorporating dates near the the root of the URI path. That way, fashions can change without requiring that pages published using older conventions be removed.

Of course, this naming scheme isn't really consistent, since the naming schemes you use inside the "name spaces" of different years might (and probably will) differ.

How to do this in a wiki, I'm not sure, though I don't take that to mean we shouldn't try. I think the mediawiki mechanism you mention is reasonable if not ideal, though this would clearly be overwhelmed if page-renaming were to become the norm. There are, as you indicate, other technical concerns. But I still think they are more easily solved that the problems that arise by failing to maintain URI stability.

The fact that we are dealing with a wiki here makes retaining URI stability especially difficult. You don't have a webmaster allocating URIs. Since the key point of a wiki is that everyone can edit, more wrong things are made at first which have to be corrected later. I want to add another point which is maybe the most important argument for being open to renamings. In the wiki, the page title affects not only the URI but it's also part of the page. It's the human-readable title you see as a part of the article. So this title *has to* be meaningful and sensible. And if this title doesn't fit into some kind of guideline for titles or is not well chosen in another regard then it is just wrong and has to be corrected. Don't misunderstand me. You have a lot of important arguments but I think that your arguments are only one side of the coin. I wanted to provide the other side. ;-)

Best regards,

#g

Best wishes, Wolfgang