A Deep Link is any link that leads users to specific contents inside of a mobile website or app, not to the homepage.
Mobile apps usually offer a better and more convenient user experience than mobile versions of websites. This makes it a vital aspect for many companies to redirect potential customers or users directly to the content they need. This can be done with deep linking. Furthermore, it is a solution for the incompatibility of mobile app and conventional web formats and ads.
E.g. if a user clicks a deep link, he will be taken directly to the searched content or product inside the application. Without a deep link, the user would have to find the mobile application on the App Store or Play Store. After opening the app, he or she would use the search function to find the product that could have been reached directly with the deep link.
Deep links are a great part for the mobile future. The main focus will be how to use them and how to guarantee best customer experience.