WorldCat/OCLC get the rough end of the Guardian's stick

Well I've always had huge admiration for OCLC and for their WorldCat service (and FindInALibrary, built upon it). My admiration has arisen in large part from the papers and reports that have come out of its distinguished personnel, and I've never known that much about its core business and how it works with libraries to make WorldCat what it is. The Guardian has a pretty critical piece (Why you can't find a library book in your search engine), which does allow OCLC's Karen Calhoun to come back but lays into a proposed rule changes that, says author Wendy Grossman, basically stops the reuse of any WorldCat data as of next month.
Now the article leaves me pretty confused about just what's to be protected. Is it the descriptive metadata about individual publications that OCLC people wrote, or data about which libraries those publications may be found in, or both? Can libraries themselves can use their own data? Does WorldCat exclude Google from its pages? Grossman would seem to imply so. I'm certainly in favour of WorldCat being truly open with a public API, and getting its stuff in all the search engines; and anything that makes it easier to know whether something is in your local library is good. AFAIK WorldCat doesn't have a really open and powerful API and this, frankly, is not sustainable. But I wonder whether Grossman is conflating metadata about books and that about copies of books in libraries in her article, in which case some of the contrasts she makes between what OCLC do and what OpenLibrary, Talis, LibraryThing etc offer may be false and unfair.

I guess I need to do some investigation myself, really. On the face of it the proposed rule change sounds unwelcome, but I'm too much of a fan of OCLC to take that criticism unquestioningly.