how is quality measured in illustration especially in social media

or if any, what are its elements, and given PRACTICE, how is good and bad split then. like perhaps in a graph so more readable
like how some thing end up being million views, million likes. so on. what are its criterias, how is it added.
a detailed understanding
especially in presentation, rather than trends like "big tea onechan" "cyberpunk" like how tos, how much, whys.