I mentioned the Mahindra Corp Blog in my previous post, if you have come late (think spiderman, "for those who came in late") then you would want to know the reasons behind a corporate blog.
There are couple of important reasons behind companies starting up a blog.
Search Engine Optimization (SEO), basically blogs are much more search engine friendly so for a company to improve it's SE ranking, it makes a blog and optimizes it for SE, this improves its SE rankings!
This would especially benefit online businesses, cause the SE ranking is crucial for their business.
Additional Public Relations, well this is another reason but it has a flip side. Definitely a blog is a more informal sort of communications portal for a company with its consumers than a website. A blog would give personality to the company which allows customers to connect with it.
Now the flipside is precisely this informal communications between the company employees and readers. Misleading and wrong info on the blog can lead to great inconvenience and bad publicity for the company.
More than this what happens sometimes is that well the customers give a very critical comment, and not all companies are up to responding well to this!