A good cause that I would like LW to talk about more is "competitive government", including Patri Friedman's seasteading project and Paul Romer's efforts to establish charter cities.
It would rock really hard to create new states to which people could move and in which people could put down roots that were better than the current options although of course there are very formidable barriers to doing that.
The art of creating and maintaining effective online communities has significant overlap with the art of government and at the current time is probably the best place to advance the art of government because the cost of trying new things and getting feedback from reality is vastly lower than the cost of other ways of trying new things in the field of governance.
Like David Brin says, it is good for each of us to remind ourselves that we or I am a member of a civilization. I take that to mean that for me to have any non-negligible hope of having a persistent (positive) effect on reality depends on my being a part of a sufficiently healthy civilization. There are some unhealthy aspects to American society, and I wish I could relocate to a society with a lower probability of my society's canceling out my efforts to improve the world. (According to my current understanding of the world, such a society probably does not currently exist.)
These sound interesting... but I assume they're politically controversial, and it may not be helpful for LessWrong to back a particular political view.
This post is prompted by a short discussion with Wei Dai. He says:
Perhaps we should get other causes to participate/recruit on LW? Actually, why aren't they here already? We have a bunch of individuals with non-SIAI interests, but no causes other than SIAI, despite Eliezer repeatedly saying that they would be welcome.
He has a good point!
Here's my plug, for the cause I spend lots of my time and energy on, Wikimedia/Wikipedia:
Wikipedia/Wikimedia is more analogous to a software project than an ordinary charity - your money is useful and most welcomed, but the real contribution is your knowledge.
Or, more generally: create educational material under a free content licence. If it's CC-by-sa, CC-by or public domain, it can interbreed and propagate.
(Then we need to fix the things wrong with the editor experience on Wikipedia ... though the Wikimedia Foundation is paying serious attention to that as well of late. In the meantime, if you find Wikipedia too personally annoying to participate in directly, writing your own site and CC-by-sa'ing it still helps a lot.)
What good causes can you think of that are relevant to LessWrong and its community, that leverage effectiveness through rationality? (I'm thinking beyond just legally-blessed charities, right down to the "small circle of conspirators" level of trying together to get something done.) As well as SIAI, LW has previously had plugs for GiveWell. What do you spend your time, effort and/or money on?