People blog because they want to share their opinions, thoughts, views, ideas, queries, news with others.
They may have a professional blog where they share views on their industry, or they may have a blog all about their pet. When you’re blogging, you can adopt any persona you like.

Many companies have an ‘official’ blog, where they release news about the company and views about the industry. Some blogs are highly successful due to the personality of the blog’s author. Some blogs have multiple authors.
Blogs can be used very effectively for educational purposes: a shared project by students can be created and showcased on a blog; teachers can post notes, lectures, FAQs and various resources on a central blog for their students.