<i>&gt; Go find someone who uses Facebook Messenger and has never heard of Hacker News. Ask them if they care about interoperability.</i><p>Many do complain about it, but can&#x27;t do much to fix it. People either end up installing 20 different clients to reach those who use other services (imagine installing 20 browsers to read different sites or 20 e-mail clients to use different e-mail accounts), or simply don&#x27;t communicate with those users when that number grows annoyingly large. This problem affects everyone, and it&#x27;s pretty apparent even to those who don&#x27;t visit HN.