First, it is fantastic to see people kicking around low-cost ideas that are potentially high-impact. If a hundred bucks could buy a meaningful change, it might be a bargain even by Effective Altruism standards. However, we should be extremely cautious to investigating such ideas thoroughly. I am extremely glad that you shared this with us before acting on it, because I have been thinking a lot about the mechanisms behind movement growth, and I think they are particularly relevant to such ideas.

It seems to me that we do NOT need movement publicity. What we need is movement advocacy. There's an important distinction, which is explained in depth by a very interesting paper by the Center for Effective Altruism.

What it boils down to is that there are two orthogonal concepts: people's awareness of any given cause, and their inclination toward or against it. For the sorts of things that are simple to explain, where people don't need any convincing, a cause can maximize its growth simply by making more people aware of it. If, however, your cause sounds a little crazy or isn't immediately obvious that it is a real problem and not hype, scam, cult, etc, then you need much more than a news sound-bite to convince anyone. In fact, a little shallow knowledge can actually hurt the cause, since the new members of the cause will be incredibly naive and misinformed, and will likely turn many, many people off of the cause as a whole. ("oh, it's those nutcases.) To make things worse, every uninformed supporter is a huge liability to the cause as a whole for much the same reason.

Imagine if the scientific community thought global warming had less than a 50% chance of being real, rather than just random fluctuations in the data. They'd have to have a nuanced argument that playing Russian roulette with the planet isn't a good risk, even if the odds are "good" (5/6 empty chambers). Then they’d still have to argue that we can and should do something about it, and that the interventions would be cost effective and successful.

X-risk has it even worse. The arguments are extremely nuanced, highly technical, and aren't definitive. (Fermi paradox, survivorship bias, anthropic reasoning, observation selection effects, and all sorts of techniques for probability assessment, to say nothing of all the specific possible forms of x-risk and all their technicalities) I think it best to concentrate on upping the number of technical papers published on X-risk, so that when we can’t keep it out of the tabloids any longer at least there will be a highly knowledgeable core community that won’t be drowned out in the media by the under informed anecdotes of “experts”. Our main (maybe only) aim at the moment should be toward academia. That might be helped by having academic X-risk conferences available on YouTube, but it would be best if academics find out about them from colleagues. A targeted advertising campaign focused on academics may be somewhat valuable, but it may also hurt our credibility. Since most people, even academics, aren’t likely to research the area thoroughly after reading an add or even watching a video, it seems quite plausible that adds could do more harm than good. I'm not saying your idea is good or bad just yet, but simply advocating a bit more discussion before committing to it. Posting here is a good way of obtaining exactly that sort of discussion, so I've upvoted you for visibility. :)

That said, if we do want to introduce non-academics to X-risk, some methods are better than others. Personally, I find it difficult not to talk about my interests/obsessions with friends. I agree with you that Nick Bostrom’s TED talks are a good start, although I wouldn’t advocate anything shorter. The Wait But Why AI article is also fantastic. There’s always a large risk that someone will read a title/headline only, and come away with a negative first impression that will be hard to correct in the future.

If you are looking for ideas of how to further X-risk awareness, I’m working on a couple ideas, but I’d prefer not to share until I’m sure they are good ideas. If I suggest a bad idea that sounds good on the surface, it would be quite hard to stop the meme after planting it, and many well-meaning people could potentially cause harm. Although there is a lot of value in informal discussions and brainstorming, it is also easier to do damage to a cause than to further it.