My understanding is wine ratings have perhaps generic-fied the taste spectrums of wines (esp. if you consider Robert Parker) but the same thing happens regardless with more information and more influx of the masses (see e.g. yelp). Or with movies. As wine became accessible to a larger audience, sure it lost some of it's uniqueness and cult appeal.
On the other hand, I honestly think that cellartracker, yelp, wine critics, this forum etc. have done so much to bring some transparency and given people confidence in their palates. For people who are intimidated by making appointments, vocabulary they don't understand etc., wine critics and user reviews truly do help.
It would have been a lot harder for me to learn and taste as much as I had when it was an industry for people "in the know."
Now as shown by this and the numerous other posts like it - where people of all different stripes of wine knowledge and education want to go to wine country.