Mac OS X Tiger: Search Technologies "The metadata engine makes searching smarter, more flexible and powerful by indexing the descriptive informational items already saved within your files and documents. Metadata describes the “what, when and who” of every piece of information saved on your Mac: the kind of content, the author, edit history, format, size and many more details. Most documents, including Microsoft Word documents, Photoshop images and emails, already contain rich metadata items. By using this indexed information for searching, you can tap into tremendous power and accuracy for refining search results."
The list of file formats are fairly standard but the cool stuff is probably the API layers. Part of Spotlight. See also, Does Spotlight == BFS?.
The example screen shots show rendering Slashdot's RSS feed and they also claim support for Adobe Photoshop. So that seems to suggest a limited support support of RDF - RSS 1.0 and perhaps XMP. Back in 2003 I found mention of metadata in OS X; it's a shame it's taken this long ;-).
And the new 30" monitors save you money. Buy 10, buy 100...