There are so many social network sites existing now on the Internet. We need to pick the right one to integrate with. Every social network service has its own characteristics. Choosing the right one to match the features and the characteristics enhances the effect. For example, if the virtual world focuses on friendship then Facebook will be a suitable one; if making funny screenshots is part of the virtual world, letting players share their screenshots on Facebook album and Flickr will be good; if the virtual world links real location in the game play, integrating the Four Square, a location-based social network service will be fun.