Bloggers as Reviewers

I was reading the LA Times Opinion section this morning regarding bloggers as reviewers.

In this piece titled, Not Everybody's a Critic, Richard Schickel writes "Sure, anyone with a blog can express an opinion about a book, but true criticism is more than just an opinion." He goes on to talk about who reviewers are and what it takes to be a serious reviewer.

I review books, both here and for ezines and print magazines. I may not live up to Schickel's standards, which I find admirable, but I feel that I have the background to review.

So, I'm curious, what do you, the reader and the author, think are the qualities that make a reviewer more professional? Better yet, what makes a reviewer article worthy? Notice, I didn't say opinion!