The Dangers of Web 2.0 According to Jakob Nielsen
A December 2007 article, Web 2.0 Can Be Dangerous ... by Jakob Nielsen, discusses why Web UIs, mashups, communities, and such often unnecessarily complicate people's lives. Dr. Nielsen, who was a Sun distinguished engineer in the 1990s, is widely considered an authority of usability: His bio quotes the many titles that have been accorded him, including "the king of usability" and "the guru of Web page usability."
Among the pitfalls described by Dr. Nielsen are complexity, confusion, and lack of representativeness. The article also contains guidelines and suggestions. Well worth a look! Even if you don't agree with all the points, they are food for thought nonetheless.