Dave Winer points to the anti-OPML questioning of an 'XML geek' and quotes the pro-OPML answer of an 'ordinary' user - "Because there are tools".
As a wannabe programming geek myself (I just never had the aptitude) I can understand, to a degree, what motivates these engineers who are almost pained by the widespread adoption of a 'sub-optimal' specification. But as Raymond says -
"OPML gives me something that xml does not: Tools that I can begin to actually use, and OPML is also a format/specification/language/whatever that is already being used out there."
And that's where the perfectionist geeks need to get a clue. I actually bought a book about XML five years ago with the full intention of 'getting into it'. But its still sitting on the shelf because my ongoing perception was that XML continued to remain obscure and impractical. It was only after I'd been happily using RSS for some time that I realized it was actually an XML spec. "My God, so this XML really is useful for something.... who would have thought!"
What was the difference between RSS and other formats, to me a lowly user? Simply that it was useful for something! And that there were all sorts of wonderful tools emerging daily to take advantage of it. It wasn't some wonderful technology just sitting in a lab - it was practical and beneficial.
And so it is with OPML. Even though most node managers working on the Open Irish Directory had never worked with it before they could immediately grok its significance. And they could build their first OPML node within a few minutes using OPMLmanager.com (or Dave Winer's own OPML Editor). Not only are editors proliferating but so also are OPML browsers/viewers including Taskable, Yabfog, KBCafe and Koz OPML.
I would like the 'XML geeks' to show me what comparable tools there are for any other XML spec?