What are the chances of NYC Comptroller John Liu being elected to the Office of Mayor of New York in 2013?

You are truly mis-informed. Being elected Mayor of NYC is NOT a necessary precursor for a presidential bid. As long as Mr. Liu is over 35 years old and American born, there is nothing stopping him from running for the White House, you could run for president as long as you meet the same criteria. I would not put any faith in anything I read on YouTube, as you well know anything can be faked and posted there...just as an example, there is a clip of Charlie Manson recording a song with the Beatles at the Abbey Road Studios which is obviously phony...my point : Don't believe everything you see.