I blog when I feel like it and generally don't feel under pressure to come up with something to 'fill the space'.
The high traffic author blogs tend to be political, championing the causes beloved of the more extreme left or right. I don't go there. I'm more about curiosities of the genre, the business of writing, info graphics, and random shit.
I do get a lot of authors asking me whether blogging is 'worth it'. Mostly they're people who don't want to blog, find it a chore to come up with regular posts, but worry that they're somehow letting themselves down if they don't - missing out on book sales that would otherwise be theirs.
So, is blogging 'worth it'?
I tend to tell the authors who ask me this question that they can probably relax. If they enjoy blogging, go for it. It might help a little. But if they don't enjoy it, just don't. My feeling is that the difference between bestseller and getting pulped isn't ever going to swing on whether you blogged.
I suspect that many people who visit author blogs are just doing it to be entertained at 'blog-level'. If I write a blog post that gets 25,000 hits (and I have) I don't think my post on the world's best selling fantasy books is going to sell my fantasy book to any significant fraction of those 25,000 visitors.
Chuck Wendig writes one of the most successful author blogs I know about. His books sell perfectly well, but he's not one of the most successful authors I know about. His blog-readership doesn't appear to have translated into a book-readership. I'm sure it helps a bit, but it doesn't seem to be a major factor and I very much doubt that's why he blogs. Additionally if it was the reason he blogged - his blog readers would probably get that vibe and stop visiting. Nobody likes to be marketed to.
So that's my take on it. This blog reaches out to blog-readers and shares my excitement and interest in the fantasy world with them. Many of those people may also be my readers, but I doubt that many of those who aren't will decide to pick up my books just because I told them what books I enjoyed last year (12,000 hits) or ran a self-published fantasy contest (19,000 hits).
In conclusion, I leave you with a hedgehog in a beaker, because the internet loves animal pics.
(wait! this is a blender!)