When it comes to a self-serve sale, an example would be something like Slack. If you don't use it already, you probably heard about it through some article, or a friend, or an ad somewhere online. The reason for this is because the problem it solves applies to you and so they make sure it's on your radar. When the Slack team was working on their marketing campaign, they could easily create a list of a ton of companies that would be buyers of their system. But when comes to Dr. Paul, getting in front of a ton of hospital CEOs to ask questions was much more difficult, and he couldn't query them in the same ways.