Pew Internet has just released a new research report on mobile messaging and social media.
— Pew Research Center (@pewresearch) August 19, 2015
You can read the report hightlights and the complete report via this link. This report, while the data is from the USA, still has some implications for Australia. It can help you work out how frequently to post the the different social media tools your library is using.
The report is also interesting to read because of how easy they have made it to tweet specific parts of if (look for the twitter icons through out the text).