When you look at the Mona Lisa or Stary Night, what do you see? What do you feel? Museums all across the globe are turning to the public to help tag the artwork seen by millions all over the world. This new style on old artifacts comes in part due to the fact that the average person does not know the name or creator of such pieces. They do however remember the feeling they got from the piece or even what they felt it was trying to convey. Museums throughout are being helped by people ranging the lovers of great masterpieces to those who find art in a bag of Reeses Pieces.
The point being that we all see things differently. Some may see the Mona Lisa and use the tags; woman, Leonardo DaVinci, bold, and some could say profound, magical, or even awkward. While tagging is a new web 2.0 idea it really has been around as long as language has been used. We have been describing things and attributing them to memory for thousands of years, however with technology ever increasing and our minds only able to retain so much information tagging is helping us to categorize and find nearly anything we are looking for.
I imagine tagging taking over our libraries and eventually wiping out the dewey decimal system. For example when looking for books on technology, specifically space travel, readers will be able to find books tagged under their desired topic rather then hunting through a barrage of numbers.