There's a good reason for having both terms. "Social network" can mean either a site that lets people socialize with each other or one's actual relationships wi

There's a good reason for having both terms. "Social network" can mean either a site that lets people socialize with each other or one's actual relationships with other people. It's usually used to mean the former. "Social graph" is used to mean only the latter. "Social networks" are the application. The "social graph" is the data.