@marmalade I agree there an issue there but don’t think it is really about push model versus pull.
As soon as someone engages outside their bubble they must hear from those outside it, but you can create a bubble with push just as easily with pull.
Isn’t that the problem we already have with MSM (push model)? Where people self select news feeds which reinforce their politics (TV, newspapers etc).
Twitter is a model that includes both push and pull. This creates diversity that makes it very hard to stay entirely within a bubble. It only takes one of the people you follow to have some aspect of difference with you too keep exposing you to stuff you might not find on a politically curated “channel” (Fox News etc).
I guess it depends whether the pull options are “pure” or not. People are not “pure” in this respect and I think our like to hear from and share with people means that were likely to end up with healthy pull & push platforms. 