My thoughts of the quote…..Back in the 19th century, the bibliographic control used were primarily for inventorising a physical item kept in a physical space eg  book collection in a library and stamps in a philatelic museum. However, this practice can no longer be used to capture the diverse information sources of the 21st century especially with digital information. eBooks for instance will not need a physical space in the library. Similarly, an online stamp museum may not need the notion of an actual physical space. Hence, I agree that it is really not about the physical form of the information carrier that matters but the actual intellectual content. This explains why search engines that use natural language may seem more user friendly.