When we build for the web, we're making websites that can be viewed in a phone, a laptop, a tablet and more. To ensure we're presenting a website that's easy to use on any device, we use Responsive Web Design techniques to modify how content is displayed depending on the viewport.
Exercise: As a group, let's brainstorm as many devices as we can think of which might access the websites we build.
See how much variety there is in viewport sizes.