Morris Dickstein:

Book review editors often have difficulty convincing their bosses that the news about books is in the books themselves, not in mega-buck contracts, bestseller chitchat, and profiles of famous authors. Truly conscientious reviewers are not exactly a beloved breed: authors sensitive to criticism detest them, publishers would love to coopt them, and academics rarely respect those who write for a wider public, not for other scholars. Yet book reviewing is where talented young critics often get their start. It encourages them to be generalists, keeping in touch with contemporary writing. It forces them to write quickly and clearly and to put flesh on their arguments, eschewing the abstract jargon of many professionals. And it contributes to a cultural conversation otherwise dominated by hot TV shows, blockbuster movies, and media-manufactured celebrities.

[…]

Though it is built on reading and writing, the Internet is seen as the
enemy of literature, digging the grave of the printed book. But just as
the computer lent new fluency to the act of writing, the Internet has
revolutionized literary research, allowing instant access to vast
bodies of information that would have required arduous labor only
yesterday. It has amplified the reach of print publications by becoming
a prime carrier of the printed word, creating a simultaneous worldwide
audience for publications great and small, local and national. But the
economic crisis afflicting newspapers and magazines, which has battered
literary journalism, shows how the Internet is eating away at it own
foundations, the printed sources of so much of its real content. The
blog will not make up the difference, at least in its unedited form as
a spontaneous effusion, a personal diary in shorthand. As Adam Kirsch
has written: “Bitesized commentary, which is all the blog form allows,
is next to useless when it comes to talking about books. Literary
criticism is only worth having if it at least strives to be literary in
its own right, with a scope, complexity, and authority that no blogger
I know even wants to achieve.” (Critical Mass)