Tripadvisor - The Tripadvisor mobile app is available for the Android and iOS platforms. It can be used to create reviews of hotels, restaurants, and to chat with other travelers on Tripadvisor forums.
Airbnb - Book unique places to stay and things to do.
Wikivoyage - the free worldwide travel guide that anyone can edit.
HomeToGo - HomeToGo is a search engine for vacation rentals worldwide.
Triptipedia - Triptipedia is a free collaborative encyclopedia of travel tips, where everyone can browse, save and share tips for better travel!
4stay - 4stay is a SaaS Enabled Marketplace (SEM) for Student and Intern housing