The Web is us, says the video "Web 2.0 The Machine is Us/ing Us" posted on The Shifted Librarian at http://theshiftedlibrarian.com/archives/2007/02/07/think_library_20_as_you_watch_this.html.
Web 2.0 is a democratic means of creating and sharing information. It's as exciting as it is frightening. Internet-based applications allow us to bypass the vetting of print publishers or software designers and instead create crowd-sourced data pools that can be wonderful for their immediacy and breadth but horrible for their ability to spread inaccuracies or banalities. I am thinking Wikipedia here, but the same is true for tags on flickr or comments on Facebook.
Perhaps the "wisdom of the crowd" is merely the "passing thoughts of the crowd"!
But like it or hate it, the era of user-as-the-creator-of-data is here, as pointed out so well by O'Reilly Media CEO and President Tim O'Reilly at http://www.oreillynet.com/pub/a/oreilly/tim/news/2005/09/30/what-is-web-20.html.
If O'Reilly is correct, the trend toward user-created data is bound to make a difference in libraries.
Will library users create "folksonomies" to replace traditional cataloging? That sounds like pandamonium to me. Perhaps it would be better if library web sites added another layer, one that would allow users to visit the traditional catalog or choose to hop on to an entertaining library web-page where they could see lists of most popular check outs, most frequent search terms, or a tag cloud with each print or digital source. As such, Web 2.0 would be a supplement to a vetted system.