Tim Bray has a thorough essay on the pros and cons (mostly cons) of inventing new XML dialects.

Tim starts by saying…

Designing XML Languages is hard. It’s boring, political, time-consuming, unglamorous, irritating work. It always takes longer than you think it will, and when you’re finished, there’s always this feeling that you could have done more or should have done less or got some detail essentially wrong.

…. which pretty well sums up the challenges with creating new document formats for the Web. Of course, we try to eliminate some of these drawbacks when doing microformats- mostly be focusing on existing behaviors on the web and aiming for the 80% use case (rather than trying to satisfy every edge case), or in Tim’s words, “do[ing] less.”

As Tim went on to describe the challenges and pitfalls of creating arbitrary XML dialects, I was already preparing a “Just use microformats!” response in my head. But, alas, Tim beat me to the punch.

Along with DocBook, ODF, UBL and Atom, he recommends “XHTML+Microformats” as a way to reuse an existing XML dialect, and thereby bypass some of the birth pains of creating a new format. Tim says:

If you’re delivering information to humans over the Web, even if you don’t think of it as “Web Pages”, it’s almost certainly insane not to use XHTML. Yes, XHTML is semantically weak and doesn’t really grok hierarchy and has a bunch of other problems.

Thanks, Tim, for the endorsement of Microformats here.

Of course, the fact that the language is semantically weak, doesn’t seem like that big a deal to me, since we can build on top of the semantics it does have (instead of reinventing things like lists, links and paragraphs). And for hierarchies of things, you can always use XOXO.

Creating new XML languages is a hard task and not likely to be rewarding. We don’t need more arbitrary formats, each with their own namespace and slightly different semantics.