I used to be freakishly good at finding my irl friends’ Reddit accounts. People tend to talk about things the same way they write. So if I had a friend who loved the Anaheim Ducks because of a specific defensive player, then it’s easy to search r/hockey for “Ducks” and then look at people’s opinions in the thread to find them. If phones are listening in, they could absolutely pick up on common phrases and opinions and find each of us. It’s genuinely not difficult.