Microformats as generally described - a small chunk of data embedded in an HTML in one of a small number of recognizable formats - makes a lot of sense to me. Yesterday I actually visited the microformats website, read the details of the current proposal … and found myself uncomfortable with the proposed implementation. Using the same mechanisms for two quite distinct purposes is usually a bad idea. Using CSS class names for both presentation and as markers for data? Sounds like trouble.

Use of a single class name (i.e. “microformat_”) would be alright if used to wrap entire chunks of data. Not much chance of collisions between use as a marker for metadata and presentation (CSS: “.microformat_ { display: none }”). Use of potentially dozens of class names, applied to the data used also for presentation? Seems like a recipe for bad programming style. The needs for use as data in a microformat and for use in presentation often differ. Better to isolate differing concerns.

So yesterday I went from generally interested in the use of microformats, to somewhat dismayed at the proposed implementation. Today an article shows up from Jon Udell expressing a similar dissonance.

XMP and microformats revisited « Jon Udell Yesterday I exercised poetic license when I suggested that Adobe’s Extensible metadata platform (XMP) was not only the spiritual cousin of microformats like hCalendar but also, perhaps, more likely to see widespread use in the near term. My poetic license was revoked, though, in a couple of comments:

Mike Linksvayer: How someone as massively clued-in as Jon Udell could be so misled as to describe XMP as a microformat is beyond me.

Danny Ayers: Like Mike I don’t really understand Jon’s references to microformats - I first assumed he meant XMP could be replaced with a uF.

Actually, I’m serious about this. If I step back and ask myself what are the essential qualities of a microformat, it’s a short list:

1. A small chunk of machine-readable metadata, 2. embedded in a document.

I do not know if XMP is “the answer” (I am tempted more by small chunks of JSON), but I am reasonably certain the proposal at microformats.org is trouble.