More often than not, we hear a one-size-fits-all answer to the question "How often should I blog?" The real answer is "It depends." Who is your intended audience? What are your blogging goals?
If you have a brand new blog and are trying to get well-ranked in Google very quickly you may need to publish a new post several times a day. Many times I've started a new blog and by posting twice a day I've been able to rank favorably in Googgle in just a couple of weeks. Not long ago a colleague started a new blog in a very competitive space and for the first month blogged six times per day. If your goal is to quickly get ranked well in Google then many short blog posts is a good idea.
Now let's consider the other end of the spectrum: Suppose your audience is the Fortune 500 C-suite, and imagine that they are subscribing to your blog and getting your posts in their email. They're not going to appreciate six emails/day.
The follow-up question of course is "How long should my posts be?" I'm a big fan of a mixture of long and short posts. Many of Seth Godin's posts are just a paragraph. My own experience is that posts of at least 500 words seem to have more impact upon Google page rankings. Sometimes however you may need 1500 words to explain a concept clearly.
If someone is busy and sees a 1500-word post they are likely to think "I'll come back to it later". The reality is that they never do. So you should always make sure you give those people something shorter to read.