With offline marketing, it's very difficult to tell how people are interacting with your brand before they have an interaction with a salesperson or make a purchase. With digital marketing, you can identify trends and patterns in people's behavior before they've reached the final stage in their buyer's journey, meaning you can make more informed decisions about how to attract them to your website right at the top of the marketing funnel.
Now imagine you had that brochure on your website instead. You can measure exactly how many people viewed the page where it's hosted, and you can collect the contact details of those who download it by using forms. Not only can you measure how many people are engaging with your content, but you're also generating qualified leads when people download it.
Inbound marketing refers to a marketing methodology wherein you attract, engage, and delight customers at every stage of the buyer's journey. You can use every digital marketing tactic listed above, throughout an inbound marketing strategy, to create a customer experience that works with the customer, not against them. Here are some classic examples of inbound marketing versus traditional marketing: https://libertymarketing.tumblr.com/