1. Blog is an easy publishing system. Anyone without HTML knowledge can post articles on your website.
2. Free advertising: Blogs are loved by Google and other search engines. You will automatically get visitors just because you post regularly in your blog.
3. Blogs are free. You can sign up online for account on blogger.com or wordpress.com. I personally recommend to host blog on your own domain name. You can use a free open source software WordPress.org, which takes about 5-10 minutes to install. If you don’t know how to do it yourself then hire a student who should be able to do that for $30-$50.
There is so many positives about having blog that there shouldn’t be any excuse not to have one. I put blog on every commercial site I own and want to seriously grow. For example this incorporation website. You are looking at our company blog.