BeWelcome - Open your door to the world!
Trustroots - Travellers community for sharing, hosting and getting people together.
Couchsurfing - CouchSurfing is your ticket to explore the world -- from the road or from your own home.
Worldpackers - Exchange your skills for accommodation
Couchers.org - The new alternative to Couchsurfing. Non-profit. Community-focused. Well built.
FairBnB - A smart and fair solution for community powered tourism.