I don’t think email is as decentralized and federated as it used to be.<p>In theory, email is a service that is simple enough for anyone to run themselves. Most Linux distros come with sendmail, so theoretically it should be as easy as reading the manual and exposing some ports. Spam is performed server side both at the origin and at the destination to mitigate bad actors, and because email is simple, there should be no shortage of clients to choose from.<p>In reality, 1/4 of all email users globally are on Gmail. Apple Mail is the most popular mail client followed by Outlook, then Gmail. SMTP and IMAP are theoretically simple, but the bellwether providers use APIs on top of these protocols that have added some functionality at the expense of restricting the proliferation of email clients. Many large companies that used to run their own email (through Exchange, Zimbra, etc) are moving to hosted Office 365 or Google Workspace. One major AWS-scale outage in Gmail or Azure will incite (and has caused) serious panic and disruption (which is great for SREs like me since we’ll continue to get paid serious money to keep all this stuff running while maintaining a healthy work-life balance, but I digress).<p>Furthermore, one doesn’t simply “stand up” their own email server unless they don’t care about landing in people’s spam folders.<p>Additionally, many companies outside of the US _do_ use WhatsApp (Facebook) for official communication. I’d posit that this trend is only accelerating.<p>I agree that email is fundamental technology, but I can see a future where it disappears in favor of something like federated Slack (or, worse, instant messaging centralized and controlled by the FAANG cabal with insurmountable cost-of-entry). Given the suppression of “free speech” on Twitter et al during peak COVID/peak insurrection (for valid reasons), this is slightly worrying.