I don't think it has collapsed. If you read early works that expanded the topic from it's original telegraphy/telephony context (e.g. Cybernetics by Norbert Wi

I don't think it has collapsed. If you read early works that expanded the topic from it's original telegraphy/telephony context (e.g. Cybernetics by Norbert Wiener) it is pretty clear that signal and noise was always subjective. Or let's phrase it differently: One persons noise could be another persons signal. Whether something something is more signal-like or more noise-like depends entirely on who is looking for which purpose. As for signal and noise in social media: Lets say you follow 5 people. If we realistically assume you are not going to like everything those 5 people post, that means your feed will contain significant amounts of noise even wothout any algorithmic curration or non-follower content. Part of that will be that you won't even know yourself what you're looking for at all times.