BeWelcome - Open your door to the world!
MyPostcard - Send real photo postcards and greeting cards - worldwide, from any place to anywhere.
Trustroots - Travellers community for sharing, hosting and getting people together.
Felt for iPhone - Handwritten cards for the modern world
Couchsurfing - CouchSurfing is your ticket to explore the world -- from the road or from your own home.
Fizzer - Send a personalised postcard with your photos. Holiday cards, thanks, greetings, invitations, birthdays and announcements.