Web performance is an important part of user experience. In this talk we will address the questions of why and how web performance matters from a business perspective. What is the real-world difference if a webpage loads in 3 versus 6 seconds? We will have a look at the available data in public big data projects to understand the performance of the Plone ecosystem. We will answer questions like how much faster or slower Plone sites are compared to other content management systems. We will then have a look at possible bottlenecks and how to address performance issues on a project and community level.