The thing is, despite doing things like posting relatively long, involved responses to YouTube hoax videos and comments by believers, I wouldn't say I've really had any impact.
I've been doing this for about 17 years now. My advice would be to reset your definition of 'impact'. If you set your sights on the goal of converting the hardcore conspiracy theorists you are bound to fail. Why? Because the vast majority of them have not come to their position by any rational misunderstanding of the evidence or logical processes used to draw a conclusion from a given set of information. As I pointed out on JR's thread, his inability to answer the question of what evidence led him to believe the landings were faked speaks volumes about his position. Specifically, that it was absolutely NOT the result of any reasoned analysis. If it were, he would have been able to immediately answer the question as asked instead of trying to divert the conversation to speculation of who might have been involved in faking it and why they might have done it (and let's not forget his entirely wilful misrepresentation of a piece of NASA evidence to make it appear to support his claim when in reality it did precisely the opposite). This is true for nearly all, in my experience. They are not concluding the landings were faked, they are
starting from that premise. That's assuming they actually hold such a belief and are not simply trolling for attention and notoriety. You can't reason someone out of an unreasonable position, especially if, for whatever reason, that premise has become so central to their identity that letting it go would cause them to melt down entirely. And even if you did, if they had been so entrenched to begin with the realisation and embarrassment may lead them to simply go off quietly and never mention it again, because for some just admitting wrongness is too much to do.
The impact of our work is harder to measure because it is less obvious, but I offer myself as an example of it. I saw the Fox special. I bought Percy's book and video. I consumed the content avidly and it raised questions in my mind about the authenticity of the landings. The idea of a conspiracy was fun and exciting. I got online and looked around for more. I found this place, I found what was then the Bad Astronomy forum, I found the excellent and informative Clavius. And they gave me information, they addressed the logical fallacies, the inconsistencies and the outright lies and prompted me to look at other publications, to find the Apollo Lunar Surface Journal, and the excellent DVD sets from Spacecraft Films. And, while I was not ill-equipped to begin with in terms of knowledge and reason, I learned. And I realised how wrong the conspiracy theories were. I turned away from the conspiracy theories because of people like you and the others here, but because I hadn't made a huge fuss about it or got into heated arguments first I would slip under the radar of anyone trying to measure impact in terms of converting HBs.
In short, don't be disheartened. The loudest voices will never be converted. The quieter ones may. And those who are just discovering it need the reasoned responses and the logical takedowns of the vocal minority HBs to counter the otherwise initially convincing rubbish spouted by them.