Blogs are used for many different purposes. Football blogs, fashion blogs, travel blogs and business blogs. Some bloggers use them as a personal diary that friends, business colleagues or members with similar interests can catch up with on a daily basis. People can touch base with each other and maybe answer each others problems. For instance it could be a political, social or religious blog. Many technology firms focus on development on a particular project. It could be a new software package that has its own blog enabling people using that program to share their experiences and help each other.
So to answer the question 'What is a blog used for' in a nut shell is a website where relevant content is updated on a regular basis, usually daily, to help people with interests or connections in a particular field of interest.To run a blog is very cheap if not free. Its a cheap way to get your message across with the biggest investment simply being time. They are a more personal presence on the internet that can help people feel your product or business is more humanized. They enable people to come across better and outshine the sometimes boring websites that don't represent people opinions and personalities. They give people a reason to return so they can keep up to date with whats happening today and how it will impact on them.
From a business point of view, blogs help customers voice their opinion about content. Feedback can be left giving valuable market research to a business helping to solve problems or make future decisions for development. If the content is compelling, entertaining and valuable then it will be shared throughout the internet which in turn picks up extra readers and links from search engines.
So to answer the question, what is a blog for, its another string to your business, membership, club or personal identity containing quality content with high promotional value. Once you discover the power of a blog, you'll be asking yourself why you never had a blog before.