Blog design DOES matter. It will affect your visitors, your commenters, and the overall time they spend on your site.
I’m not going to lie, I enter giveaways every now and then whenever I have a chance. And I’ve found some blogs I just HAVE to revisit, and others… that I wouldn’t exactly want to go through the torture of visiting again.
You are running a blog, an outlet you want people to stop by and read. And if you’re a book blogger, you most likely want publishers to send you ARC’s. That means publishers have to INVEST in you. They’re snapping off a portion, however small, of their marketing campaign by sending you one, two, or five ARC’s.
If I were a publisher, I wouldn’t want to send a review copy if a blog is as dark as some of their covers with font the color of blood. Does that mean your blog shouldn’t be dark? No! By all means, make it dark, (I’ve even designed some dark blogs), but always keep in mind, a dark background should have easy-to-read font. And if your background is cluttered to the extent that I can’t stay focused on your content, then, well, I wouldn’t really want to stay.
And sidebars. Sidebars shouldn’t be cluttered either. I’ve visited blogs with two sidebars, filled to the brim with images of books, images simply for the sake of visuality. Stop. Its just too much. It makes me want to pluck out my eyeballs and cover them with a blanket. Pictures are pretty. Sidebars are meant for filling. But note the difference between filling and cluttering. And try to leave some space between your post content and sidebars.
Lastly, whatever colors you use and content you choose, ensure one thing: Make your visitors feel comfortable, at home, at ease. Make them want to come back.
ETA: A few awesome comments brought this to my attention: loading. Some of us have set our blogs to post more than 7 of our most recent posts on our home pages and have flash widgets that make a page take eternity to load. Your blog isn’t the only blog out there, don’t make your readers leave, draw them in. Make your pages load faster. Make your visitors stay longer.