Jon Udell has the following entry: Truth, files, microformats, and XMP.

It's interesting to me because I'm working through in my mind how to take a GPS GPX track file, Virtual Earth, and a bunch of photos taken over time near the GPX track file, and merge these all together, allowing the meta data in the photo to have lat / lon info inserted in (or updated).

Mr. Udell's article then led to:

Microsoft Photography Blog, and

Professional photography with Windows XP (see downloads for the Microsoft Photo Info tool).

As more useful metadata both gets into photos and is exposed by photos to be manipulated, really interesting scenarios come into play, especially around the photos you collect from friends and family.

What will be especially interesting is if thumbnails expose a bit of this metadata as embedded microformats, allowing search engines to do more accurate search results for media.