OpenURL, still active?

I saw an RFP the other day talking about the "OpenURL" protocol, which 
I'd never heard of; I looked it up at 
http://library.caltech.edu/openurl/ and it seems to be a standard for 
how to pack a whole bunch of bibliographic selectors into the query part 
of a URI, which sounds sensible to me.  There don't seem to be any 
updates since January 2002, is this one still alive? -Tim