Why? Because it's not delivering leads.
SO, at risk of paraphrasing to the point of inanity, here are a few tips to fix your blogging. I'm keeping it short because clearly, mine needs work!
TrackingMake sure you know:
1. What are people saying about you?
2. How many people are responding to your calls to action?
3. What is your conversion rate?
4. What is your sales rate?
5. Rankings is (sic) old school (why? because they're tailored for individuals these days)
6. Conversions by source
If your blog isn't delivering on these kinds of metrics, think about whether you're actually achieving anything at all.