OCLC Usability

Was surfing OCLC (Online Computer Library Center) following a library list message and thought it was interesting they have a section devoted to describing their Usability process to customers. Would be interesting to see if other information services offer information about how they approach Usability. Haven't seen that from other content aggregators like Dow Jones Interactive, Dialog, etc. I don't even know if Dialog knows what Usability is, judging from the complexity of their search interfaces.