If you’re a writer-o’-books, the answer to this question is “depends on who you ask.”

Miss Snark has recommended that novelists be cautious about blogging — because when you’re blogging, you’re not working on your novel. But she also wrote, once, that a “well-clicked” blog can be a plus when you’re querying agents.

Late last month, John at Romantic Ramblings recounted the advice he got from his last agent, who told him a blog was practically indispensable.

But John also found a warning on Agent Query that a blog may be a liability rather than an asset for writers looking for representation. (What they are really trying to say, I think, is that a poorly written or presented blog can be a liability. Which is true, I’m sure.)

So now, to add another twist to the conversation, comes this: Joe Garofoli, in the San Francisco Chronicle, reports on how political blogger Glenn Greenwald was able to coordinate online publicity for his non-fic book among his like-minded blogging buddies. The resulting burst of orders pushed his book to number 1 on Amazon.

Granted, Amazon is only one reseller, so if your book is ranked high there, but isn’t selling anywhere else, it doesn’t really mean much.

Except that you get to say your book is a number 1 Amazon best-seller. Certainly better than a poke in the eye with a sharp stick.

So what’s the verdict? I’d say it’s something like this. Don’t blog if you tend to use it as an excuse to avoid doing the real work of writing. Don’t put up a sloppy blog, or a cheesy blog. Don’t present a virtual persona that comes across as loony or raises red flags about your people skills. (Of course, if you have people-skills problems you probably don’t know your blog comes across that way but that’s a whole ‘nother topic.)

And last but not least, remember that blogging is really a type of networking. If it’s going to help you sell books, it’s because of the relationships you’ve built, not because you’ve mentioned your title and now it shows up on Google.