Three main reasons to start a blog:
Simple and easy
A blog is easy to setup and maintain. It is very economical and user friendly, both for the reader and the the blogger who maintains the blog. WordPress is the widely used blogging software around. It is a database driven program that makes blogging easier and starting a blog faster. Self hosted WordPress blogs give more authority to the blogger than free Blogspot blogs and blogs hosted on WordPress.com. Its basically the free WordPress software running on your chosen web host. With lowering prices of web hosting charges, setting up a WordPress self hosted blog has become quite affordable.
WordPress blogs are by default SEO optimized. That means they are taken well by search engines. Getting listed on a search page is vital for traffic. People can find you while they are looking for something. Writing useful content with related keywords makes your posts ranked faster and in prominent locations. With WordPress, it all becomes so easy, you can hardly imagine in blogger or other blogging platforms.
Publicize your content
If you having a business, I would recommend you to start blog. This is highly beneficial, regardless of the costs in setting up a WordPress blog. A blog has a casual friendly tone and a reader takes up that as a good advise for buying stuff from you. Having your own domain makes it easy for you to be accessible. Showcase your products, give them your contact information for queries and when they pop up a message, give them your quote. Its all so simple and yet profitable. But before that get a WordPress guru to assist you in setting up a blog and help you from time to time.