I don't really think so. The people who seek out specific documentaries are probably doing so for a reason. Not a lot of people are willing to sit through a three part documentary like Zeitgeist unless they're at least vaguely interested in the topic. Popular documentaries that make the rounds largely have no 'teeth,' and that's why they become popular. Think of Michael Moore's documentaries, they're about hard hitting social issues, but they make you laugh, they make you feel good, and most importantly, they're filmed like many narrative films are. Documentaries that have 'teeth,' and actively work to change society are usually specialized, and people have to seek them out.
that's just my 2BTC. I've recently graduated with a minor in film (nothing special, I know), but I did take a course on documentary films.
I agree. I think "mainstream" critiques like Jon Stewart's Daily Show, while always lacking in a call to action, will probably always be most widespread in getting a message out, even if ineffective. I disagree with most opinions (usually presented as smear pieces) in that show, and even find only 1/4 of it to be actually entertaining, but I watch it anyway. Jon will even poke fun at his paradoxical role, and insist he's a comedian, not someone who should be "setting the tone" for conversations in America as he's accused of. I've also watched LaRouche documentaries on recommendation from a friend, which I think could be considered "toothy." Neither has ever convinced me to do anything, so I'd think it's fair to assume both of them ineffective at changing anything. - And I know, it's unfair to say "I've never done it, so nobody does," but I've never really heard of anyone recently talking about Benghazi or the VA paperwork fiasco outside the Internet.
All that said, I think 20/20, 60 Minutes, and similar shows are and will always be the most effective -- we've seen them make major changes in US politics, with new SEC regulations on insider trading definitely being the big outcome (though... IIRC, they were already on the books, so....). I can't think of any examples of "movie"-type documentaries ever having that kind of societal impact, because they really aren't watched by many people - and when they do, it's generally because they're funny.
- But then, what about Super Size Me? I can no longer get super-sized food, and we all know what happened in NYC. I watched it and was amused, but I think Fat Head was also amusing and presented a more compelling case than Spurlock's film. Neither really made me want to change anything... so maybe a debate over the effect of Super Size Me and the changes the US consumer saw after are warranted - but I think we can reasonably attribute at least a significant amount of weight toward societal change to the release of Super Size Me.
I'm going way off on a tangent... I think media which targets people early (most religions are excellent at this!) will always be the most persuasive. I really like John Stossel's "In the Classroom" series, because even though they have a significant bias (especially in more recent Fox-released DVDs), they're ultimately about encouraging independent and critical thought. In the DVDs, they include teacher resources, so it can become an actual lesson, with a very significant outreach while being very cost-effective (in fact, I was shown one of the first Stossel in the Classrooms DVDs by a teacher who was simply excited to have something new and free available in his toolkit). If we believe a revolution is warranted in some area, there is surely no greater means of producing it than by promoting sentience among humans, and I think that's ultimately much more important than promoting any single issue. We all know that in the typical "American" conversation, it's like talking with a completely thoughtless version of Chuck Hagee or James Fallows - or just asking "The Bible" its opinion on whether or not God could create the Immovable Boulder. We know sending these non-sentient beings to college doesn't work, and I think it's the same with documentaries in most cases - so how do we effectively get to "The Influencers" in our society? Maybe more importantly, who are "The Influencers?" Frankly, I think it's just the current generation of "old people." I don't think we can fundamentally change their way of thinking, only offer them facts to show them something the majority of "old people" believe wrong. With young people, though (and I'm talking 8-18, not 28-38), I think a much stronger case could be made that we CAN fundamentally change how they think, and maybe more importantly - WHY they think. I think a lot of documentaries ultimately fail (not in terms of revenue, but in societal change) because they target people who are set in their ways, but not very influential -- the majority.
ETA: To be fair.... I heard a lot from my friend on LaRouche. At first, I thought it was hilarious some old guy was blaming climate change on some far-off "Crab Nebula" I never heard of in school. After actually researching it - a result, partially, of tangential learning from LaRouche videos - I find myself believing many of his general theories plausible -- not necessarily that the Crab Nebula is responsible for climate change... and I still think it's funny anyone could believe "The Queen" is involved in hard drug trade.... but still... documentaries by him and his "associates" ultimately have affected what I believe and how I think, so maybe they could be considered effective - at least in doing
something.