Revisions are a new way to track changes to your tree and discover new collaborators. Revisions are built on an entirely new technology that will enable some great features in the future, including the ability to undo changes to your tree and compare different versions of profiles. Today you can view a list of revisions for a tree or profile. Each revision is a record of activity, such as a merge or a profile update. Revisions are a great way to see recent changes and find other users working on the same parts of the tree.
Read the full blog about Revisions at the Geni blog.