Yahoo bought WebJay

I read about this on the 9th in O'Reilly Radar.

SearchEngineWatch Blog has a good story as usual: Yahoo Acquires Webjay.
In it Gary Price points out the Yahoo Music Blog.

I think it is interesting to speculate exactly what they are buying.

(I guess I should say first what Webjay is: a music playlist sharing community.)

Web 2.0 buzz?
A user community?
A standard for exchanging lists of music tracks?

This last one interests me.
Suppose I have read a bunch of interesting journal articles online.
How should I bundle up the references to them and send the info to you?

A list of DOIs?
A bunch of raw citation information you have to process in some software of your own?
Connotea links?
OpenURLs?
EndNote or some other citation format?

Unfortunately this rapidly starts to edge into territory in which librarians are quite expert, and in which I am totally lost.  I can copy and paste a list from some conference blogging I did at InfoGrid 2005...

need XML-based representation for compound objects
- many options MPEG-21 DIDL, METS, IMS/CP, RDF...

UPDATE 2006-01-14: XMP

I don't actually know the details of what any of those are.