Interesting point about SNR, social network and moderation. Ten years ago, when I interviewed for the Chinese clone of Facebook(renren 人人网), I told that the one of the major problems of social media is the SNR, and my interviewer insisted it was a feature problem. I didn't get the job, but within 3-4 years, renren goes downhill, and today nobody uses it anymore. Increasing SNR is actually a difficult question, because user behavior doesn't actually mean signal, something that is eye-catching, click-baity, is actually a good signal for the user. Something interesting about Tiktok is it was designed for optimizing SNR, especially, only having one item(which is a video) each screen, instead of having a list of content. This, and autoplaying videos was breaking all the rules of app design guidelines. Now it is copied everywhere. So how does Tiktok influence SNR, if user behavior does not compeletely correlate on what the real signal is. The secret recipe for Tiktok is human moderation, not volunteers, but tens of thousands of people, curating, moderating, to complement its realtime recommendation system.