Now in the days of Google and Amazon do we cataloguers still need a controlled vocabulary?
In my opinion the answer is a resounding YES! Computers and library database software are so particular that even a misplaced comma or period can create a new authority. One of my pet peeves is the careless use of genres. For instance I have downloaded many records that use the genre heading “Romantic suspense novels”. There is no such heading in LCSH and the correct term in GSAFD is “Romantic suspense fiction“. We do our patrons a disservice if we have both of these heading in our database. The same goes for “Detective and mystery stories” (an LCSH heading) and “Mystery fiction” (a GSAFD heading). Each library should pick which heading they intend to use and stick to these.