Tagging, Folksonomies & Technorati in Del.icio.us

Tagging is an open and informal method of categorizing that allows users to associate keywords with online content.
Technorati tagging, is a social bookmarking manager which allows you to bookmark a web page and add tags to categorize your bookmarks.

Wikis

Another site that the ordinary reader can find and contribute good reading material for other like minded readers. Seems to be a large variety of topics.

Could be used as a rss feed on our next reads site.

Public Libraries could set up a Wiki as Princeton Library has and patrons could publish their own reviews on books they have read from our libraries.