I think someone should make a YouTube series that covers effective altruism in a broad, accessible way, similar to existing shows in the YouTube educational content ecosystem such as SciShow.
The show would start by introducing the core concepts and main focus areas of EA (global health and development, animal welfare, and improving the future), and then dive deep into each of those areas over the course of several videos. There could also be a few videos on other causes of interest to effective altruists (such as criminal justice reform and improving science). Each video would be about 10 minutes long, and new videos could be uploaded on a monthly to weekly basis.
The purpose of the show would be to get viewers interested in effective altruism and inspire them to take action and start engaging with the EA community; indeed, the YouTube channel would be creating a new community space for effective altruists. As such, the show should respond to what viewers are interested in seeing content about rather than promoting a particular EA cause or philosophy.
There is some social validation for this idea: for example, Kelsey Piper has said that she would be excited if someone created "a YouTube for effective altruism."
Last year I've created a channel on effective altruism in Russian and made five videos on various topics, focusing mostly on introduction to main cause areas and fighting popular misconceptions on foreign aid (no English subtitles available, sorry). Each video was ~10 minutes long and they got >4000 views in total. With videos, I reached a 50 times larger audience than with offline public talks, but it was very time-consuming. I spent around 30-35 hours on making each video and eventually stopped making new ones, even though the audience was very friendly and people still reaching me out almost every week and asking about new videos. I'll be happy to share my experience in making these videos if needed.
I think that creating a community space on YouTube and creating high-quality videos would be valuable, and I'll be happy to hear if someone does this. But the conversion rate from YouTube viewers to actively involved EA members could be very low. That's why in my videos I focused mostly on fighting ignorance, introducing ideas/books/research/organizations, and creating a better culture of charitable giving without actively promoting EA.
Strongly agree with that, I think the show should introduce viewers to ideas & opportunities rather than promote a particular philosophy.