Speaking the Graphing Social Patterns conference (covering the business and technology of Facebook) in San Jose today, Linkedin founder and chairman Reid Hoffman poured cold water on the notion that a single social graph would prevail. "One graph that includes all types of relationships in one perfectly orchestrated universe is a geek, blogger dream. It's not mass market," Hoffman said. "The amount of effort in building and maintaining it is hard. It may be important to have different baseline rules for different brands and different networks."
"The simple misconception is that any communications infrastructure can be used for anything. The question is what is the use case. The interesting overlap is public profile presence in search engines and the potential business applications that can be built on the social graph," he added.
Just as one Web site cannot be all things to all people, and there won't be one graph binding them all, Hoffman said. "Diversity is part of what makes the ecosystem good and interesting for consumers."
Hoffman, who is also an investor in Facebook, explained how Facebook and Linkedin offer different use cases. Linkedin is about affecting business and has more context than Facebook around that use, he said. Linkedin, for example, recently introduced photos to its site (head shots of members), but not photo sharing. Similarly, Linkedin Answers is more tied to professional reputation and providing expertise compared to the more general Facebook answer applications.
The Facebook messaging and communications platform is about sharing, and Linkedin is about brokering business relationships, meeting someone you don't know and finding professional connections, services and jobs, Hoffman said.
Of course, Facebook is still in its infancy and could grow up to create a branch for business users. The company is expected to announce soon that members will be able to categorize relationships, e.g., friends, family, business.
Hoffman was asked about linkage between his business-oriented social networking site and Facebook. He paused for a moment and said, "We are going to probably going to provide some apps on Facebook. We have one--My Company is Hiring--but it has no traction."
"We will provide professional apps to the degree the audience wants them. It depends on how much energy or investment they are worth," he added. "Our interest is in making sure people can make themselves effective day-by-day and week-by-week."
"You can't just build random applications for it. I would speculate from other parties not having done Facebook apps yet, it is less about fear and more about return on investment." He noted that there are big niche opportunities for entrepreneurs given that large companies can only launch two or three interesting businesses a year.
I asked Hoffman about APIs that would open up Linkedin's platform for developers, which he mentioned when I talked to him June. He said that APIs would be forthcoming but did not say when.
Facebook's platform is unique among social networks in the way it allows developers to acquire customers, leverage key relationships and leverage the existing communications scheme to build interesting applications, Hoffman said. However, as reported in O'Reilly's report on the Facebook Platform, 87 percent of the usage goes to only 84 Facebook applications, and only 45 applications exceed 100,000 active users.
Facebook and other social networks work because the patterns of important relationships you have in real life are manifest on the Web and in the case of Facebook empowered by useful applications. "If you can import relationships that matter and enables applications, you can change peoples lives," Hoffman said.
Hoffman pointed out that communications and entertainment applications, such as those from Slide, RockYou and Facebook, are the biggest. Future possibilities for successful applications would include iterations of major use cases today, he said, and those that would be useful in a one-to-one, one-to-many and many-to-many environment with your friends.
Hoffman also pointed to Facebook photo sharing as a best case of what the new pattern of communications looks like and Web discovery through friends and sharing as a future direction for search.
He expects that new entrepreneurs from college will first write Facebook applications, mostly around social entertainment. The challenge for developers will be constantly creating something new to keep people coming back for more.
He noted that the Facebook Platform is a microcosm of the Web. "Rising above the noise is more difficult because it is so easy to write applications," Hoffman said. "What hasn't worked so far [on Facebook] is business, politics and money. A challenge for developers is the "second act" the economics of the Web.
"What is still up in the air is the establishment of new use cases and major applications. Anything you try to charge for someone else will give away as way to acquire customers. At least three people will try to copy whatever works," Hoffman said. The key factors are how to get distribution, usage, retention and some economic return, he stated.
According to Lance Tokuda of Facebook application developer RockYou, only one percent of Facebook applications succeed in getting distribution of any consequence. That said, Tokuda also said that Facebook is seven times better than MySpace as a distribution platform.