You can't always read or think over every potential piece of interesting content at the very moment when you happen to see it, so you need a way to gather all that possibility into a place you can return to later, for deeper reading, insight, and inspiration.
There are many apps for and approaches to clipping content. For media makers and visual artists you want to look for an app that allows you to clip a wide array of types of content such as images, video, text, files, and provides a large amount of storage for those files.
Try visualizing your topic to explore all of the different angles, ideas, and key concepts related to your topic. This is a good brainstorming exercise and can also help focus your topic into a research question.
The tools below can help you visualize your topic.
Citations aren't just for pasting into the bibliography of a research paper. Citations are the fundamental details you need to keep track of any kind of information that is important to you. Think of citations like a kind of smartphone contacts list for the sources that have the most influence on your work.
Even if you're not formatting sources for a paper, you still want to be able to keep track of the most important sources you encounter so that you can "get in touch" with them again later. Some citation managers are very basic, while others allow for note-taking, file uploads, and have social sharing options.