How about this? Work out the audience share of a service, then work out the audience share of its nearest competitor/competitors. If the former is twice/four t

How about this? Work out the audience share of a service, then work out the audience share of its nearest competitor/competitors. If the former is twice/four times/whatever as high as the latter, then it's counted as a de facto monopoly and regulated. So YouTube's got 74.08% of the market and Vimeo has 18.02%[1], and the former is definitely twice or four times more than the latter, so regulate the former. [1]https://www.datanyze.com/market-share/online-video--12/youtube-market-share https://www.datanyze.com/market-share/online-video--12/youtu...