Marketing is more than showing products and describing them. It is about building a relationship with potential customers so that you will be able to sell to them. The best way to build that connection is through adding a blog to your website.
If people trust your blog and your brand, they are going to be more likely to trust your company, which means more sales. With a blog, they get to know what is important to you (or at least your bloggers), whom they assume are aligned with your ideas and philosophy for your business. They also get something from you without you asking anything in return (information they need).
Where did blogging start? Some give credit to Justin Hall, a college student who wanted a place to keep his writing. It's more likely that Justin started it as a blog website in 1994, then others picked up on it until it got to be a "thing" with people wanting to do blogs all over the place by 2003.
Whatever the case, today, a blog is more than a place to put one's thoughts or experiences. It is the lifeblood of a business and if you don’t have one–you should get on board. As Bill Gates, former CEO of Microsoft, once said, "Content is king. Whoever is a part of creating content will be the next billionaires."