From a viewer perspective, although there are people who came to Youtube for knowledge, cooking recipe, live competitions, and news, most customers came to Youtube for entertainment including watching vlogs, makeup videos, or music videos/ playlist. Viewers don't need to worry about what they used to watching. Moreover, you could find almost every aspect they would like to dive in. The Youtube community has everything that their customer want.
From the "God's eye view" perspective, the Youtube and Youtuber market is very mature. It has stable and increasing number of views and also more and more youtuber that could also attract more exposure. The viewers of Youtube could be mainly divided into two parts: people who came to watch entertainment videos such as music videos or vlogs and other people. Looking at the relationship between different categories of their videos, there is a high relationship between science and technology; travel and events; and howto and style. It is worth to pay attention these categories because that also shows what people could think of after watching one video. Therefore, the direction between each video becomes clear which will not only benefit Youtube but also viewers.
From a time perspective, the data from 2017 and 2018 didn't show much difference. As what has been said above, Youtube has a very mature market which means normally it will not have some huge changes. Therefore, for future reference, analysis on data from 1990, 2000, and 2020 could be performed. We should be able to see the growth of Youtube.
From a peer perspective, the result for Bilibili cannot even compare to Youtube. Before the project, one of the questions that needs to be answered is how Bilibili compares to Youtube in their video types, viewers, viewer preferences, etc. However, the market of these two video websites are far from similar. Bilibili started with a website that contain mainly animation/ cartoon videos, and then as time went by, comic channels became popular. Bilibili recently began to have many youtuber-like channels. Therefore, no matter which aspect, Youtube and Bilibili cannot have a proper comparison.