From DIQA Projektmanagement GmbH
Search result refinement with the term tree is now available for Office 365 and SharePoint online.
The TreeRefiner Add-in Part provides a search refiner for your search center in Office 365 and SharePoint online that displays a tree of terms that are contained in the search results. It complements the SharePoint-refiners and can be added into the search center.
Get your Evaluation Copy for your O365 Tennant: open the Office Store