Trustroots - Travellers community for sharing, hosting and getting people together.
Pack - Makes it simple to find the best roommates.
BeWelcome - Open your door to the world!
Roomr - Discover great people to live with
Hospitality Club - Free network of people around the world who offer free accommodation, advice and help when they are traveling - hospitality exchange. Free membership.
OurFlat - Groceries, bills, calendar, chores & chat for any household.