MyPostcard - Send real photo postcards and greeting cards - worldwide, from any place to anywhere.
BeWelcome - Open your door to the world!
Felt for iPhone - Handwritten cards for the modern world
Trustroots - Travellers community for sharing, hosting and getting people together.
Fizzer - Send a personalised postcard with your photos. Holiday cards, thanks, greetings, invitations, birthdays and announcements.
Hospitality Club - Free network of people around the world who offer free accommodation, advice and help when they are traveling - hospitality exchange. Free membership.