For those who are familiar with QuickPlace, it's not a surprise but a good news.
QuickPlace is built on the paradigm of nested rooms: a Quickplace is a Tree of rooms with the root as the Main room where you manage member access.
Each sub-room allows a group of people using the Quickplace to manage activities or projects of some part of the group: access rights with according roles are granted to members to support the organizational goals.
With QP before 7 release, rooms had to support another use case: Document and Folder clustering: i.e: support for document classification.
It was not wery handy! Document classification usually requires many levels and you needed also to manage access rights to those clustering sub-rooms without any benefit... Plus, the navigation of QuickPlace is one level at a time, which is good for few rooms, but get quite confusing when you reach multiple levels. Now, browsing a folder with the tree of subfolders is implemented as a treeview in the QuickPlace table of content.
Hence, you have a clear distinction between classifying documents into nested folders and group activities breakdown supported by sub-rooms.
Nice feature: thank you to Lotus QP dev team.