Your argument seems to hinge quite heavily on the premise that all these other social media giants are competition for Youtube. I am sure you do this because you have looked at the numbers and realized how heavily Youtube dominates the market and therefore the only potential way to continue your argument is to try to lump them all together. They essentially provide different services, and furthermore Youtube is used WITHIN these competing services quite heavily. Just because you can subscribe to people and message them does not make it more social media than video media any more than Twitter is a video media platform because it can host video media.
Another convenient tactic I noticed you used was to limit your numbers to unique monthly users, because again you know the real numbers don't support your argument. The real numbers are not unique monthly users but video views, because that is how everyone gets paid, and since Youtube already dominates the market it is largely a matter of HOW LONG the users spend on the site, and Youtube dominates that in spite of your attempt to skirt around it. Lets look at the real numbers for their ACTUAL market competition: https://www.statista.com/statistics/266201/us-market-share-of-leading-internet-video-portals/
https://www.theguardian.com/technology/2015/jul/07/youtube-240bn-monthly-views-mcns
As you can see Youtube enjoys a 78.8% market share as of late 2016, with 240 BILLION monthly views. Essentially EVERY PERSON ON EARTH views an average of 34 videos a month. Arguing they don't enjoy market share domination is asinine. When using these statistics nothing else comes even close.
Well you found a favorable definition of monopoly to better suit your argument, but a monopoly is fundamentally a legal terminology with very specific definitions and standards. Lets examine them.
The two primary determining factors for designating a company a monopoly are:
(1) the firm has a high share of a relevant market and
(2) there are entry barriers... that permit the firm to exercise substantial market power for an appreciable period.
"If a firm has maintained a market share in excess of two-thirds for a significant period and the firm s market share is unlikely to be eroded in the near future, the Department believes that such facts ordinarily should establish a rebuttable presumption that the firm possesses monopoly power."
As you can clearly see Youtube fits WELL within the legal definition for monopoly regardless of the fact that legal action hasn't yet been taken against it. Youtube part of the parent company of Google enjoys quite heavy government support thru it's parent company Alphabet seeing as it had early investment in it from the CIA holding company called In-Q-Tel:
https://en.wikipedia.org/wiki/In-Q-Tel
So, because of these government ties it not only enjoys a monopoly, but also government protection and special benefits, so it is unlikely to ever be challenged in court without significant public pressure. Thanks for the debate, it was interesting.
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