Shared Grocery/Store List (A Helpful App)

My husband and I started using the Any.do checklist app several months ago, and it has been so helpful in ensuring that our grocery and store lists are current and accessible by whoever is at the store.  This handy app is on our iPhones and integrated into our Chrome web browsers, which means that we can easily add and check-off items from multiple locations (the updates happen across devices in real time).  If we are running low on something, we have trained ourselves to immediately add it to our list.  If one of us is at the store, we just have to check the current list for that store (we have a list for each of the main stores where we shop).  Such a time and communication saver, and errands are much more efficient now.  Do you have any tools that you use to improve efficiency and communication with your significant other?  If so, please share!