Cards are fast becoming one of the best design patterns for mobile devices. They collect individual pieces of content aggregated together into one experience.

We are currently witnessing a re-architecture of the web, away from pages and destinations, towards completely personalized experiences built on an aggregation of many individual pieces of content. This is a result of the rise of mobile technology, which resulted in billions of new connected devices, using different resolutions, pixel densities, and form-factors.

The idea behind cards is to show the user only relevant information at the right time. This way user focuses solely on the most important message, while most clutter is removed.

The best time to use cards would be when we need to show a particular bit information, deemed important to the user at a given time. While the card approach could be used all the time, the way Twitter separates tweets one from another, this is not always practical.

There are many services and websites already using the card system to display information. This way they visually separate or highlight information.