a) Grunt and nod in my direction simultaneously
b) somebody/everybody/nobody/anybody while glancing quickly in my direction, trying to be subtle. “Somebody needs to take care of this problem but everybody seems too busy to bother”
c) socialize online in environments similar to this one, having deep-ish public moments with a large variety of individual humans once but not so deep as to get a private message
d) You can learn something positive and useful from almost anybody if you just listen.