1) content created by amateurs is not filtered the way traditional media is, meaning that there is a lot of garbage available (this ranges from poorly produced videos andun-edited blogs to material of dubious accuracy ranging from 9/11 conspiracy films to Neo-Nazi web-casts ) 2) much of the material are re-mixes of existing material, leading to piracy and lessening demand and respect for the original creator's work 3) related to the other two, the Internet is harming society because of the acceptance of common, perhaps morally dubious, if not illegal, practises.
Perhaps it's worth noting that Tim Berners-Lee's original web browser allowed editing as well as viewing web pages (though this editing ability was forgotten when Netscape launched the Internet boom a few years later). So maybe the Internet was never going to be a television transmitter or a printing press, rather an open market of ideas (good or bad) rather than a centrally-planned system.
He frames much of his arguments in economic terms; How user-created content is killing jobs by letting amateurs perform the work of experts, or by diluting the authority of experts, leading to their work becoming only one voice among many in the battle for authority. Two websites singled out areWikipedia and Craigslist. Wikipedia , for putting researchers out of work and, though it's anyone can edit policy, facilitating the well-known problem of government minister's aides, company public relations departments and assorted nuts from all parts of the political spectrum editing articles to suit their tastes.Craigslist, in turn, is hurting newspapers by taking away revenue from their classified-ads. The assumption here being that the classified-ads belonged to newspapers as perhaps a free Hotmail account stole from the fax machine. Unexamined, however, are the traditional media companies, no doubt driven by the twin desires of profit and relevance make them culpable in this too. For instance, he states that user-generated commercials are taking money away from professional film staff: "$331,000 not paid to filmmakers, actors...$331,000 sucked out of the economy" (p.63), yet he seems more annoyed at the people doing the commercial than the company that presumably saved itself 330K.
In the 2nd half, "The Moral Disorder", Keen focuses on a range of social ills, from a pre-teen who downloads music and is sued by the American recording industry to the story of an honours student who becomes an gambling addict and ends up robbing a bank. Mixed in with this are the usual bits on child molesters running around and other assorted depravity and peppered with such gems as "pornography and file sharing addiction". The problem is he freely mixes gambling with identity theft or file sharing with pornography, morally dubious to criminal with the implication being that these things are all one and the same.
Ultimately this approach will drive some readers away who might be receptive to his ideas, but to be fair, he's open about writing, "a polemic about the destructive impact of [the Internet]" right from the first page. Many readers will find fault with his arguments, but it doesn't make this any less worth reading.