Using proprietary chat apps like Discord, Telegram, Slack, LINE, Meta’s WhatsApp / Messenger. Still judging on apps that require a SIM & mobile OS (like Android) primary device like Signal… or an expensive chat protocol like Matrix.
Hosting your code & bug tracker with a propietary forge like Microsoft GitHub when you say you support open source—but don’t even bother to apply the same mentality to your own project.
…Oh, the question was “secretly”.