Well…
If you follow the link to fedidb, refer to the “mau” monthly active users. Do some brief math and realize that lemmy.world accounts for about 50% of all active users
Email market share is harder, but many estimate that Gmail accounts for over 40%. Many many orgs use Google apps to make custom branded gmails with their own domains too
This is the typical “business power law” that states that the top player should control about 50%, the second player about 25%, etc. This is just kinda how the world works
That’s so cool, maybe the first time in the history of humanity that we see open source tax software, that’s guaranteed to be accurate to the law. For one year at least
It runs Scala / Java, and has docker configs, decent documentation. And an ominous message explaining that some parts were too secret to open source so they had to rewrite chunks of it. Overall, it seems like it was a big project just to get this published, and I am impressed they managed it, given the software team was comprised of 3 different agencies and several contractor firms