Google have today sent a security warning about W3W, with regards to Google Drive:-
Remove risky access to your data
This app or service has extensive access to your personal information and its developer's information hasn't been verified by Google. You should remove its access unless you're sure you trust it. Learn about the risks.
Has access to Google Drive
I don't really understand why they need access, or is this to store any locations I've saved? Should I rescind their access? Are they really going to look at anything else I have that's on Google Drive (not that I would put anything sensitive on there).