They understand you can send e-mails without needing to have an account with the same provider. They may not know it under the name federation, but they do understand the relevant part, for them.

Right because the UX is so good, thus the conversation

People don't understand how e-mail works because the UX is so good. They understand it because it is ubiquitous and they are used to it. They don't expect anything else to work like that, because nothing else on the internet they use works like that. There is no UX to fix this. People just have to be taught that this is an option.

Can vouch for that, after having run first an ISP in the 90's and then a webmail provider a few years later.

The number of people I had to teach about the "@" symbol alone. And then a few years later the pain was gone. Enough people had learned that most people asked their friends and family rather than need tech support.

The tipping point comes quicker than people expect. E.g. many of the discussions on Mastodon on Twitter is already full of neophytes who had never heard about federation a week ago who are now explaining it to others.

I have no illusion this wave here and now will be the watershed for Mastodon, even with 10x-20x as many daily signups as a couple of weeks ago (currently the hourly signups are above the daily signups two weeks ago), but every wave makes the next one easier.

I would disagree, most people know that they can write to both [email protected] and to [email protected], and that they are people using different services.

Phone numbers with area codes are still a thing?

@[email protected] shouldn't be too hard to wrap their head around.

I think the parallel is that people don't click on a link to send an email to someone for the first time. They copy and paste an email address into the "To" field of their email client. Same thing with getting someone's number to send them a text. And they know that people use different-looking email programs to read their email. Many people use the iPhone mail app on their phone and web mail on their computer. They don't know the word "federated," but the differences aren't alien to them.