WHAT IS A BLOG
In fact a blog is a type of website. But it is different from a complete website in following aspects:
Most of the famous organizations have their official blogs. Even Google, Microsoft, Twitter use blog to communicate with their consumers. As the contents of blogs are regularly updated with fresh topics, they can easily get higher rank in the search engines. An organization usually publishes new offers, news updates, notices for the customers through blog.
An individual may also have a blog. A personal blog may be created by Blogger's, Word Press etc. Personal opinions, experience can be shared by these types of blogs.