Hi Karen: I definitely think adding COinS to OpenLibrary pages could make sense. I'm curious what everyone's use case is. Is it mainly browser plugins that can inject links to a relevant OpenURL router so that you can find books in your local context? If so I think use of COinS in OpenLibrary makes a lot of sense.
There is an orthogonal use case of making structured metadata available via a book display. I'd personally prefer to see web pages for books include auto-discovery links for alternate machine readable representations. This is how blogs are typically tied to their atom and/or rss syndication feeds. For example if the web page for Weaving the Web [1] could include something like: <head> <link rel="alternate" type="application/json" href="http://openlibrary.org/api/get?key=/b/OL7290708M" /> <link rel="alternate" type="application/rdf+xml" href="http://openlibrary.org/b/OL7290708M.rdf" /> ... </head> The JSON one works now of course, the RDF one is hypothetical. A consuming application like Zotero (or a web crawler) could then use simple auto-discovery to find the machine readable data. Another alternative would be to use RDFa to interleave metadata into the HTML display itself. We have nice things like the Bibliographic Ontology, and the emerging RDA vocabulary that you are working on which would fold right into these RDF representations. This machine readable metadata could also link to things like the PDF, table-of-contents, etc where appropriate. It would be great if Brewster's idea of "a web-page for every book" could also mean machine readable metadata for every book. OpenLibrary has a rich database available behind it it, and it seems a shame not to expose it in the HTML in a web-friendly way. //Ed [1] http://openlibrary.org/b/OL7290708M