Such as:
For one day the only tweets you can see are from people with 2+ children
Everyone's tweets or icons or something else are marked with colors indicating the above
Etc
Even if optional, it counts. Even if only temporarily available. As long as at least 1% of users can see it for some period of time.
By mid 2028
@jskf Once I realized that the culture of the people currently making up SF, NY, etc will die out, mostly childless, it changed my view. They'll convert more people from other areas to sustain it, but still, that whole worldview is dead man walking. I think about it a lot, and it's so sad cause I like what they (we) create. So I've been thinking about various projects to highlight the massive difference between people, which won't show up obviously for 20-30 years, such as a browser extension which highlights all names according to whether they've sustained themselves biologically or not. I like diversity of language, culture, ideas etc and it's really sad to see huge groups just not making it and getting ready to disappear (south korea, japan, SF, NY, people with PhDs)