When we receive a submission at Greenleaf Book Group, we vet the content of the book for its marketability. We consider the audience it serves, the author's credentials, and whether or not there are already other popular books on the exact same topic. Often someone will pose the question, "Would this be more successful as a blog or a book?"

Yes, many authors write a book and blog, but both serve a specific purpose that the other could not replace. As this Harvard Business Review article points out, there are events and career opportunities that are almost inaccessible if you haven't written a book. On the flip side, there is a world of people online that you're not reaching if you're not blogging.

Even if you plan to write both a blog and a book at some point, the decision comes down to which one to write first. If you're unsure whether your message will be more effective as a book or a blog, here are some guidelines to help:

When It Should Be a Blog

It's Time-Sensitive

Unlike traditional print books, a blog can easily be updated or corrected with new information. If you report on new social media platforms, for example, trying to compile a book on the latest trends will take longer than the trends will last, and you'll likely never catch up fast enough to be able to sell the book. While a quality, traditionally printed book takes time to produce and can't be changed quickly once it's published, a blog can begin today and change course tomorrow, no sweat.

It Lacks Credentials

You may have spent the past 28 years perfecting a diet and exercise plan that has helped your family get fit and stay healthy, but if you're unknown and not a certified nutritionist, people will question your authority to write an entire book on the subject. You might be able to publish and gain traction by word of mouth, but it could cost tremendous time and resources for little return.

Conversely, blogging on the subject you're passionate about gives your audience a chance to try out your advice in small pieces. If they like it and think it works, they'll share it with their friends, and over time you'll build a following of people who would be interested in buying a book that you write down the road.

It's Looking for an Audience

If you're passionate about your subject matter, it's easy to assume that everyone in the world will want to learn about it, too. This assumption can become dangerous when you're unknown and planning to print a couple thousand books. If you're not 100% certain who your audience is and don't have evidence to identify them, you could be left with a house full of books that didn't resonate with people like you thought they would.

In contrast, starting a blog is a low-cost, low-risk way to find out who your content is attracting and why. Tools like Google Analytics can help you identify the demographics of your audience. If they're not what you expected, you can either adjust your blog or adjust your expectations without hesitating under the weight of time and resources already spent on a book.

When It Should Be a Book

Its Message is Timeless

Books can go out of date like anything else, but there is a reason that we deem some books classics and continue to reference them throughout history while others fade away. Great books resonate with people across circumstances, and they contribute to contemporary conversation, even if the book was written 100 years ago. If the ideas you're presenting are rooted in the nature of humanity or in time-tested, unchanging methodologies rather than trends, your book could continue to guide people for years.

It Solidifies Your Credibility

If you've been working in your industry for 30 years and are transitioning into a career as a consultant or speaker for your area of expertise, writing a book can create opportunities that a blog usually can't, like invitations to speak at conferences or to consult for large companies.

One of the main reasons that a book builds so much credibility is its permanence in contrast to the fluidity of a blog. Though blogging is hard work and has its own learning curve, the journey of writing a book requires a notable amount of courage and commitment. You can't easily delete a book once it's out in the world.

It Has a Following

Whether your audience has grown from your work as a consultant, from media attention, or from content you've created on digital platforms, there comes a time to offer your faithful, well-established followers something tangible. Unlike a blog, a book exudes permanence and an extra level of care and attention that your audience will appreciate.

Though many authors end up both writing a book and blogging, you begin by focusing on one or the other. When you take time to analyze your content and figure out why you want to share it in the first place, you'll be able to choose the path that's right for you.