Nowadays, sharing is a trend for many people. The car sharing service was born in Europe, and now is available also in the US, and Japan. Sharing some luxuries are not only economical but also ecological.
Very recently, I found a social networking service which offers users matching accomodation. Its name is Airbnb. You can register on the site with Facebook or Google+ account. Many landlords provide the information of their house and you can book any accommodation with low cost.
House sharing is advantageous especially for travelers and students who want to save money for staying. In addition, it helps the users to communicate with each other. It would be an impressive experience.
On the other hand, I am concerned about security. I believe most users are sincere, but if a few people with menace registers on the site it would be dangerous. Since this kind of services is based on the mutual relationship of the user, I guess the service providers cannot intervene the negotiation to solve some troubles. Instead, they demand disclosure of personal information and equip some reputation systems. However, these schemes are not enough to avoid trouble completely.
I expect that this kind of services will be spread and our society will get more matured in the future.