The realization also made me wonder: what's the most-watched show on the Internet? The reality is: Nobody knows. More, I am not sure that many folks would even agree on the definitions in the question. When talking about Internet video viewing, the concept of "most-watched" is vague to begin with. Are we talking about most uniques to a site, streams on a site, streams in syndication, views on YouTube, podcasts or in banner video autostart advertisements?
Further, when we think about online video shows, it's hard to identify what qualifies as a "show." Are we talking about television shows watched online, professionally produced content distributed online only, content within a vertical section of a video site, and/or content created by advertisers as a means of positioning it as something other than an advertisement?
I would propose that the "most-watched" measurement should be the highest number of user-initiated streams in any distribution category that is measurable online and that a "show" is any periodically produced branded content.
It is important that these standardized measurements have protection from being gamed. Nearly every lofty claim about wide show distribution includes an enormous caveat such as whether the video was autostarted below the fold with the sound off, or whether users thought it was a bikini video when it was really a McDonald's ad.
Once we come together and figure out a standardized definition for what the most-watched show would be, we should encourage that single show to be independently measured by comScore, Nielsen and Quantcast to present an apples to apples comparison with other comparable entities.
Only then can we begin to have the discussion about the claim of the most-watched show on the Internet. This reality would then beg the question, "what does this mean and why does anyone care?" I leave that one for you to answer for yourselves.