Jon Udell has a screencast and a discussion of photo tagging in the Vista Photo Gallery: Tagging and foldering in Photo Gallery.

While I think tagging is a cool geek idea, how do you make it more automatic, and if automatic, how do you make it correct and useful? Let alone inter-op with all applications, beyond the OS, that want to use the tags?

One thing that worries me looking into an XMP is that XMP is going to become like RSS: littered with namespace extensions of companies and people who don't understand what's already there or people who don't have a foggiest notion of well-formed XML (e.g., Apple and it's initial audio-cast streams).

Think if you had to write an RSS feed parser (really simple syndication, right?): how many special cases and work-arounds would you have to put in?

Meta-data is on the edge of falling into the same pit.

(Oh, and P.S.: it's a shame that the first comment on Jon's post above is someone ragging on him for being Microsoft focused on the technology being covered; get-over it! Go blog yourself about how great some other piece of technology is and don't have such a shallow sense of self you have to rag on someone for not tooting your horn.)