This document summarizes a study examining evidence for echo chambers and filter bubbles on Twitter in Australia. The study analyzed follower connections and engagement patterns between Twitter accounts with over 1,000 followers. It found limited evidence of highly exclusionary echo chambers or filter bubbles, except for some specialist clusters. Most accounts had more external than internal connections or balanced engagement. Retweets generally spread information more externally than @mentions. The study has limitations but provides little support for strong exclusionary information silos within the Australian Twittersphere.