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YouTube began hosting videos in 2005. Of course, not too many people were aware of the video-sharing site that would later become a viral-video juggernaut. At that time, most videos were spread to friends using email or old-fashioned word-of-mouth, making it difficult to track the popularity of a video. Many of the first videos uploaded to YouTube were already considerably popular on the Internet, but YouTube made sharing them much simpler and provided a means of gauging their popularity.