I'm wondering if we might not be better off if fairly frequently we do get exposed to the best arguments against $MY_IDEOLOGY, and not get trained into the idea that $MY_IDEOLOGY is the one true correct ideology.
Beyond such, being dropped into a bunch of other bubbles will probably force you to come up with stronger arguments for your ideology, which is, all in all, growth and arguably a good thing.
The rest of the time, we just have a very hard time abandoning our beliefs. (I know It'd be hard for me to admit that functional programming is not superior to class based programming most of the time, even in the face of compelling evidence. I'd be likely to search for an escape hatch first.) It's truth that's important, but, probably because of the mind projection fallacy, we mistake our beliefs for truth, and therefore holds our current beliefs dear, which is rather silly when you think about it.
By the way, if being dropped in other bubbles compels you to find stronger arguments for your own, beware that those stronger arguments may actually be unjustified rationalizations. That would be a bad thing. Better change your mind in that case.
Fortunately you can train: http://wiki.lesswrong.com/wiki/How_To_Actually_Change_Your_M...
Do you let the user control it? That's great philosophically, but I think in practice it will be hardly any different than search engines just intelligently twiddling the settings based on your actions. On the other hand, pretty much any answer other than the user creates even larger problems with conflicts of interest.
Eli Pariser did a great job of selling the idea that we should be exposed to true diversity, but I still fear that in practice the truly gut, visceral reaction that people have to this is that people can end up in $NOT_MY_IDEOLOGY bubbles, and what they really want is going to be less about diversity and more about making sure that people's bubbles put more of $MY_IDEOLOGY into everybody's bubble (as $MY_IDEOLOGY is obviously the one true correct ideology and therefore deserving of special treatment). There are a lot more people claiming to value diversity than there are people who truly want people to be exposed to the best arguments against $MY_IDEOLOGY there is.