Most of the posts here were about big corporations like Apple, Sun, Microsoft, GM, who are in blogging. But I should say, that early adopters of blogs were really small companies and at most individuals. What are the benefits for small businesses?
- Blog software is easy to use. Simply write your thoughts, link to resources, and publish to your blog, all at the push of a few buttons. Blog software companies such as, Movable Type, Blogger.com and Radio Userland all offer easy blogging tools to get started.
- Blogging is a low-cost alternative to having a web presence. For small business owners without the time to learn web html or the money to hire a designer/developer, blogging offers an inexpensive method to get your company’s name out on the Internet.
- Updating the weblog is a much quicker process than contacting a web designer with changes or doing the coding and uploading yourself.
- Business blogs provide your small business with a chance to share your expertise and knowledge with a larger audience. A powerful benefit for consultants and knowledge workers.
What a Blog Can Do For Your Small Business [about.com]
Better business communication 
I would like to see a continuation of the topic