Trolls are going to be a problem on Periscope, Twitter's live streaming app, since streams are open to strangers. Anyone has been able to view other streams since the app launched but an update brings a follower-only mode that should at least partially deal with trolls.
Since accounts are linked to the social network, some trolling is combated, but people can create accounts that have no personal connection. So, if someone wants to protect their stream and avoid trolls, they can now do so.
Twitter is also making it easier to block people during a stream. Tapping a user brings up the option to block them.