This cannot be stressed enough. One of the key factors in traffic to your site is frequently updated content. Since (ideally) this is all content that is relevant to your business/product anyway, the only discipline lies in regular posting:
What are some reasons to have a blog? Bruner said, "Blog stands for Better Listings On Google" because Google favors regularly updated content. It's also common for breaking news to be featured on blogs.
The article also does a decent job of defining four categories of blogs -- Thought Leadership, Customer Relations, Peer Marketing, Media Relations. The comments about "monetizing blogs" are not correct, I think. Or rather, your goals for maintaining a blog are very different if you want to directly make money from it, i.e. through advertising or sponsorships, rather than maintaining it for its own sake.
You might maintain a blog to demonstrate your expertise or opinions about a range of topics. This in turn might lead to paid work or opportunities that you would never have if you didn't publicly write about them. In the past, this might have been done through an opt-in email newsletter or infrequently published, longer articles.