I’m guessing that TripAdvisor was not the only medium customers were using to complain about their terrible experiences, just the most visible. As user generated content now dominates the web and has an incredibly vast reach, all businesses are vulnerable to online backlash as a result of a poor experience.
So don’t ignore negative reviews until they blow up in your face and show up on the front page of HuffPost, get a shout out from the evening news, etc. Granted these are extreme examples, negative reviews aren’t always just useless rants. You can almost always pull out common themes such as parking, unfriendly staff, etc. This information is pure gold if you’re looking for ways to improve, and generally represent very easy fixes. Note that none of the hotels from the 2010 list were on the 2011 list – likely it got their attention.