This post makes me wonder how notable a practice or activity needs to become before it makes it into Wikipedia. Are half a dozen people doing this or is it a we

This post makes me wonder how notable a practice or activity needs to become before it makes it into Wikipedia. Are half a dozen people doing this or is it a well-known common occurrence that is been documented on several occasions? If it is documented, do I just have to document something before I can put it in Wikipedia? Where is the line there?