How to Export a List of Yammer Community Members

If you're moving a large number of users to another community or looking to copy a list of users from Yammer you can do this very easily with tyGraph for Yammer

Steps

1. Go to the Group Activity Page 
2. Filter to your Community, you can use the search at the top of the list to find your community faster
3. Click "Switch to List Community Members Below"
4. Click the ellipsis (...) at the top right of the table.
5. Click Export data and follow the instructions for exporting to excel.

See this for details on exporting to excel. Export data from a Power BI visualization - Power BI | Microsoft Docs