I must thank the gods that he's not on television here, nor do we have an equivalent (Finally, the ACMA comes in handy).
From the material provided (The transcripts and the videos), as well as some slight independant study via Youtube videos, I'd have to conclude the guy is a grade A moron who hates alot of people. I'd prefer he wasn't on any television simply based on that (Does that count as wanting him off because I disagree with him Monster? Do I get more respect?

). My brain can't comprehend the intelligence of some who are taken to be reputable sources, but I suppose those who take them at word value are just as bad if not worse.
But, is he dangerous? From the outside looking in, I'd say no more than any other idiot. People who take in his arguments are going to believe that stuff anyway, they've just got a convenient way of getting the information. Much like people who are mentally challenged, and actually act on his words are going to find people to attempt to harm (In this case, 'Liberals') regardless.
http://www.youtube.com/watch?v=YA7-BvVDV10
http://www.youtube.com/watch?v=A7NUQZiWl6w&feature=related
Hilarious to listen to, moreso for the fact that it appears people can take him as a reputable source.
Personally, I find people like Paul Popoff more dangerous than a uncoherant man on a soapbox.
Disclaimer: The above is from the perspective of an Australian looking in at this, and giving his take on it. It should be taken as such.