the stories are good, the blog posts, not so much
This is a book on five acts.
The first act you have the stories. In this act, "The Diary of Jane Sagan" and "God Machines" are going to get stuck in your head, 'cause they are pretty excellent stories.
The second act are blog posts, which are meh.
The third act is a single story, which is ok.
The fourth act are more blog posts, which manages to be more Boeing than the ones in the second act.
The fifth act are unused chapters from "Lock In". They are probably good, if you read the published story.
Now, while the stories are good, the fact that 70% of the book are blog posts is a real let down, mostly because I think blog posts are boring. Sure, there are exceptions to this rule, like Wil Weathon's book, in which he just don't put the posts, but actually put some background about them. For Scalzi, there is no such reflections and most of the posts are not even interesting, 'cause they are temporal or regional (like elections and things related to the USA). After a while, I just skipped most of them.
Is it a worth book? Hard to answer. If I had only the stories and no blog posts, that would be awesome, but the posts just make the book longer without the need for such.