Clutter is a term that refers to the excessive amount of competing messages or advertisements within a communication environment. The sometimes excessive number of ads or non-programming content that people are exposed to while watching television, trying to read a blog post, or scrolling their social media feed, could make it difficult for any single message to stand out or to be noticed by the audience.
Usually, but not always, the tall and narrow form factor of contemporary smartphones helps reduce clutter because, especially in social media feeds, only one or at most two messages are displayed on the screen at a time. Therefore, even if two ads appear consecutively, users can still see and comprehend them if they choose to do so.