From an author’s perspective, how beneficial is Blogging?
I think it's important to differentiate Blogging as a social tool from using a Blog as a marketing tool.
If you're "selling," your blog content is going to be far different from that which you might use for say, establishing and maintaining a public presence... although some manage to do both.
There are hundreds of Book Blogs on the web, created in lieu of a website because it allows for interaction with readers in a way that a site cannot.
As to content? Like a website, most post a synopsis and maybe a sample chapter linked as a read-only content page, with links to research, the publisher and any other web presence you may have.
The rest is just marketing.
It's not direct selling ... It is marketing...by establishing and maintaining a presence in the social network infrastructure.
What it should not be used for is over-hyping your book(s). That is a guaranteed way to turn people off, and in the end your hype becomes seen as just another source of Spam.
How effective is marketing by social networking?
How many people bought a book because of what they read in a reviewers column in the trade presses or on a book review Blog or on a paid for book website, or simply via word of mouth... or because it was on the discount table at the local book sellers?
I haven't found any statistics to prove that any one medium is more effective than another.
I can say that book ads on Blogs are noticed, that book blog sites are reviewed by reviewers, and that in a time when the majority of the worlds societies are largely 'plugged-in', social networks like Facebook do help make the connections between book and author which does in the long run have a positive impact upon sales.
The important point is this: In today’s world of lower budgets and increasing scrutiny of costs by the bean-counters... and especially if your books are published by a small imprint or POD publisher, the onus on marketing... on getting what you've published out into the public eye and creating an interest in it... is largely on you, the author. That means using whatever venues are available.
Whether any venue is worth the effort, depends upon how you answer the next question.
How badly do you want to sell your book(s)?