A blog is an online weblog or journal that can have one author or many and is generally focused on a particular topic. For example, DeMicco.com is focused on Marketing, SEO, and Business Development tips, technology and information.
A blog is a great way for you to communicate with your target audience groups in an informal manner. They can also be used effectively to support your search engine optimization efforts for your online assets (like your product websites or brand sites) by generating backlinks to your targeted web pages relevant to the topic of the blog post.
For example, if you market running shoes and athletic wear to runners then your blog is a great place to discuss topics interesting to runners. Within these blog posts you can include links to your products that offer a solution to the concern raised in your blog post. Encourage your readers to comment and to return to read more posts by keeping your posts interesting and useful.