OK...
I have a theory, Which I've wondered about for the longest time.
Well, when you go to Google and type "Guitar" Guess what shows up in the results?
http://www.google.com/search?hl=en&q=G...mp;aq=f&oq=Thats right Funtwo's Famous clip.
Same thing with Youtube. Out of Millions of Videos of guitars, Funtwo gets put right at number 1.
http://www.youtube.com/results?search_quer..._type=&aq=fAnd, I've Got to imagine the word "Guitar" gets typed into google and youtube, at least 100,000+(probably even alot more than that) times a day from People All over the world.
And most of the people who search "Guitar" will see the video clip, and click.
And for alot of people who don't know much about guitars or are beginners they will see Funtwo and think he is like a "Guitar God".
Not to take anything away from funtwo, he's definitely a very skilled player,
But I always like JerryC version alot better as well.
So to answer the original question, I think part of the reason he's so popular (and has over 54 million views) Has got to be getting put at the top of the search results.