I organise AI Safety Brisbane - there are no AI safety orgs in Brisbane, or even Australia, so before ever forming it, I had to consider the impact of members (including myself!) eventually leaving for London or the Bay Area to do work there. While we don't actively encourage people to do this, that certainly is the goal for some of the more committed members. 

My general way of handling this is to openly admit that I expect some amount of churn as a result of this, and that this is a totally reasonable thing for any member to do. I've also been considering plans for how to manage handoffs in a similar way to EA university groups, where we know that members will eventually graduate out of the group. I haven't faced any resistance over admitting this dynamic openly thus far - this may change in the future if we get Brisbane-based alternatives, but we'll cross that bridge when we come to it.

I like the idea of keeping in touch with "alumni" of the group who head overseas to pursue impactful work!

This is really important! I think it definitely makes community building much, much harder when people leave. And I definitely have noticed the tendency to think that your community is worth building (vs. going to another place and doing community building there - which I think in many cases is probably more impactful and better for an individual's career). n=2!

I do want to acknowledge (and I feel this is not really covered in your post) that it can be pretty emotionally difficult to accept - and I don't think it's just tribalism. I think it's hard to accept that people like you in your city will probably (at least in the near future) just have a worse off experience finding EA than someone in a big hub or university. I feel this way about my own journey - I got lucky that there were a couple super EA people in my college, that I found them, and that we became good friends. These friends are a big reason I went to my first EAG, answered all my questions, sent me Forum posts, and got me involved in community building. But everyone won't get such a supportive or smooth journey, and that makes me sad.  

Thanks for posting this! 

As a community builder in Hungary, this is something that will be more and more relevant for us. I think I am probably less worried about "EA brain drain" than the average community builder outside of big EA Hubs, but some of my thoughts are:

(Epistemic status: the lower the claim is in the list, the less confident I am in  it, criticisms are welcome!)

-In the end, it's really the given individual's personal choice as to whether they stay with their local group or move to EA hubs. As a community builder, it doesn't seem right to me to try to nudge people one way or the other. (Apart from giving my best advice on what I think will have the biggest impact, help thinking about trade-offs etc.)

-Plenty of people will stay with their local group for personal reasons.

-It would be nice if most EA orgs wouldn't require moving for roles that are possible to do remotely. (Although there might be strong reasons to have people in one office, I didn't think about this much before)

-We should definitely keep in touch with people who move away and have them as (online) speakers, and ask them to have 1-1s with new but promising members.

-If it's the case that most of a group's impact will come from the few most engaged individuals, it seems that we should do everything to support those engaged individuals have +x% more impact than worry about what would be best for our local groups.

-It might be valuable to have more local EA-orgs, in low and middle-income countries (maybe). Even if these won't produce the biggest impact, they can be a stepping stone for people to skill up and join international orgs, and given that operations costs should be lower in those countries, it could be still cost-effective to run them. (Although I suspect this would work better for some cause areas than others, eg. I could see it working well in animal welfare, but less so in AI Safety).