Before search engines, there was no way to know the exact words that a large group of people would use when thinking about a certain topic. Oh sure, you could ask a small group of people, but anyone who has ever done focus groups will tell you that what people say in front of others is not the same as what they will really do.
If you’re writing any type of headline, online or off, you should be doing search engine keyword research. Because any great headline should speak in the language of the audience, while wrapped up in a time-tested structure that catches attention and offers value. But it gets better.
Any SEO pro worth listening to will tell you that you don’t go after the most popular keywords. You target the niche phrases. They may result in less traffic individually, but there’s a lot more of them, and less competition.
This is perfect for writing headlines for humans. The niche phrases are much more specific, and specificity makes for a much better headline.
Further, better headlines lead to better content when you write the headline first. Google and the other search engines really do want to reflect what’s important to people. That’s why they use links and anchor text as one of the primary determinations of relevancy.