I highly recommend the full report on the results of the Library of Congress Flickr Pilot Project (as well as the fascinating collections of images).
The statistics are impressive, and the analysis of tagging behavior is interesting. And, when you finish reading, you can wander The Commons, an unexpected public good that resulted from this collaboration between Flickr and the Library.
Strange Connections
The glittering allure of the mobile society by Alan Moore of SMLXL provides useful data and insights about search, interactivity, and the pocket Internet.