Blogging for small businesses is a great way to attract and retain customers. One of the ways a small business blog can attract customers is by helping the main small business site score higher on the search engines. Another way to attract customers with a small business blog is by making the blog itself rank higher on the search engines, and to get higher search engine ranks on keywords and phrases that are related, but different from the words and phrases the main site goes after. This widens the net cast for customers, and the symbiosis between the blog and the main site helps both get higher search engine ranks.
To help small businesses manage their blogs, I've started a blogs for small business program. As an example for small businesses, I have started two blogs where you can learn more about using blogs to help a small business. One is Supak Blogs for Small Business Blogs, and the other is Search Engines Higher Search Engine Ranks.