I am considering adding this tool to my genealogy toolbox. This seems like a good way to collaborate on dead-end relatives with multiple researchers. It also looks like a good place to gather stories of a common ancestor from descendants with different perspectives and traditions.
These two uses are clearly not the only ways in which this site/tool could prove useful, but these are the ways I am thinking of using it right now. I encourage you to have a look at werelate.org, and let me know what you think of using this tool for genealogical collaboration and sharing.