Why I started this blog – in terms of career development

As a software developer, one of the best mediums you can use to market yourself is a blog. It's my firm belief that every software developer who cares about their career should invest in creating a blog.
You can only meet so many people in person, so you need another primary way to market yourself and network. Think about how many people you’ve met in the tech industry over the past year. That number might approach several hundred, or even a thousand, but a successful blog could introduce you to hundreds of thousands of people.
A blog is a cheap and easy way to market yourself and it’s extremely valuable for getting your name out there. A successful blog can attract hundreds or even thousands of visitors per day, which can give you many opportunities ranging from job offers to consulting gigs or even an audience to sell a product to.
Quite honestly, I owe most of the success I’ve experienced in my career to my blog. If I hadn’t created a blog and figured out how to make it successful, it’s unlikely that you’d be reading this book.

(Citation from the book – why the author thinks a successful blog is important)