When they say "bubble", I think of groups of users with fewer differences within the group than outside the group, sort of like the Wall Street Journal study sh

When they say "bubble", I think of groups of users with fewer differences within the group than outside the group, sort of like the Wall Street Journal study showed. If they're finding variation among users, but not predictably more or less variation between any two of them, then that isn't a "bubble" to me, it's just customization. Customization is troubling, but less so than bubbling. (Hey now...)