I don’t think it implies that others who’ve used the same tag mean precisely the same thing, just as is the case in folksonomies such as del.icio.us.
You don’t have to link to Technorati’s tag space if that doesn’t suit you. You can link to any tag space you like.
Have a URL allows readers to see some explanation of the tag. For example I link my tags to wikipedia often (even though I work for Technorati :)). The wikipedia explains what I mean by the tag. Technorati tags are useful in that they say “this post is a part of that conversation” and work pretty well for that.
<span rel=”tag”></span> is not valid (X)HTML, nor is the ‘rel’ attribute meaninful in this case. As it is defined as: “describ[ing] the relationship from the current document to the anchor specified by the href attribute.” With your proposal, there’s no relationship to describe.

As I’ve said before regardin author tagging vs. reader tagging, it is obvious that they are different and and have different benefits. But I don’t see why this is an argument against author tagging- they’re not mutually exclusive.

“Since the only part of a tag space URL of which any structure is required is the last segment, a tag space URL can be hosted at any domain.”

http://microformats.org/wiki/reltag#Tag_Spaces

Maybe a URL-free version of this idea would have been better, but it’s not true that Technorati has excluded other players on this point.

A question: what tag spaces are people actually linking to out there? I’m guessing it’s mostly Technorati and a smattering of Wikipedia and del.icio.us; any other significant targets?

Hi Prentiss,
My concern wasn’t with any technorati-centricness of the scheme - it’s clear technorati are being very open and keen to produce standards for the benefit of all. Just that I wasn’t sure the URL portion added any value in return for its additional complexity over a simple tag, and may have implied semantics* not adequately supported by the scheme.

(i.e. ‘I mean the same as all the other people using this tag in the tagspace’)

Hmmm.. Maybe. I guess I’m stuck on URIs=precision because I’ve been so involved with RDF in the past.

<span rel=”tag”></span> is not valid (X)HTML, nor is the ‘rel’ attribute meaninful in this case. As it is defined as: “describ[ing] the relationship from the current document to the anchor specified by the href attribute.” With your proposal, there’s no relationship to describe.

Oops - that probably should have been <span class=”tag”>apple</span> or something.

Further, for many websites it is difficult to implement a URL w/o a file extension i.e. IIS5 and IIS6 based websites, for example (note that this fact infuriates me [see http://www.mikeschinkel.com/blog/WellDesignedURLsAreBeautiful.aspx], but it is still a fact.)

What’s more, RSSBlog has a great point about re=”tag” contrbuting PageRank inappropriately: http://www.kbcafe.com/rss/?guid=20050619130051

L:astly, it doesn’t allow associating meaning of a tag with a URL that doesn’t end with tag itself, which to me is very limiting.

JMTCW