Why are product managers important?
Most technology giants such as Google and Facebook have talented product managers for successful businesses. Product managers are those who continuously create the valuable products from users' perspective. In the era of smartphones, the product manager's role has become so important, but why? It is mainly because of the high speed changing of the digital world with products and human beings.
Previously, manufacturing products were developed by engineers or researchers, in other words, they were usually developed by product-out. In most cases, this way of development leads to improving its performance without any necessity and adding many features that users might not use. Eventually, users have to wait for the new updated product that will be released in few years or something, even though users have felt the product is not good to use.
In the Internet industry, a product should be developed from minimum viable product (MVP), then gradually and quickly updated based on the problem that users face. This is the big difference between previous manufacturing products development cycle and recent software products development cycle. The important thing here is always to focus on what kind of issues users have faced, not what you want to develop. Engineers or researchers have a tendency to place more emphasis on technology, but it becomes harder to grow their businesses in that way, because the tech-based specification does often not completely match with users' requirements. Since the users' preferences are changing quickly in these days as I mentioned, product managers always have to make sure if the specification is defined based on users' requirements during every single agile development cycle.
The responsibilities of product managers are basically three: acquiring new users, increasing customer satisfaction (retention rate), and improving profitability. To achieve them, product managers are required to clearly explain "why, what, how, who, when" to all stakeholders such as engineers, marketers, sales, designers, testers, legals, etc. Product mangers are sometimes described as a translator between each stakeholder. Even though the decision was made by engineers for example, I believe that product managers should understand it and be able to explain it to others in an appropriate expression in order to work smoothly with cross functional teams.