That's also a major component for larger subs, but I do actually see the same people over and over in small subs (my city, etc.) if I bother to look at username

That's also a major component for larger subs, but I do actually see the same people over and over in small subs (my city, etc.) if I bother to look at usernames. My eye isn't drawn to the usernames as often as it would be drawn to avatars.