I very much agree with Fred Wilson and Albert Wenger that we construct various social networks, not just one, to suit various needs. One’s Facebook social graph is often the group of people with whom you are comfortable sharing light-hearted info and photos. One’s Foursquare graph is often more limited: the group of people whom you want to know your physical location. Your Twitter graph is really an interest graph and I think, over time, less about people and more about information sources. Your Venmo graph is even more limited: those people with whom you exchange money and trust. Facebook, I think, could have developed additional functionality sooner to provide impetus to construct these additional graphs (often a subset of your FB graph) directly with them, but I think they missed this. They have been too slow to recognize the importance of physical location, were late in allowing asynchronous following, and are now getting around to payments. None of this is likely to impact their continued massive success, but it opened up opportunities to others.

Missing from this discussion is what I find most interesting about social media: the graph most important to monetization. There are interesting businesses being built on top of the graphs discussed above. However when you really want to build an enormous media business on top of the ridonkulous amount of social data available on the web, you find a new graph emerges: the brand social graph.

At Media6Degrees, the company has pioneered the ability to assemble custom audiences for brands from the connections between their customers and those customers’ friends. For any particular brand, the company actually computes (all anonymously, of course — no personally identifiable info is involved) a brand social graph, finding the friends of a brands’ customers most likely to be interested in actually buying the product. It turns out this is much harder than simply advertising a product to everyone in someone’s social graph. We have multiple connections between us as people, and some are more predictive of mutual brand affinity than others. The brand graph can change by the day, ad campaign, product or offer. This is a hard data problem, but one whose rewards are enormous.

The brand social graph is a big idea. I think, as social media matures, friend targeting via a brand social graph will be a significantly large business model for the largest media companies. Perhaps one qualification: the search targeting model dominated by Google is still likely the most effective form of advertising ever created: the user’s intent is entirely clear, so advertising works really well. But it isn’t great, as we all know, in building brands, finding audiences and creating demand. Brand spending and demand creation is a much larger part of ad spending than demand fulfillment is. I think these needs will largely be served by friend targeting in the future, and one which Facebook is in the position to dominate (but it not yet doing). Google, Yahoo and Microsoft all have enormous amounts of relevant social connection data but do not yet show evidence of using it. Many of Facebook’s announcements last week put it in the pole position of delivering web-wide friend targeting when they deploy an ad network on top of FB Connect one day. And Twitter’s interest graph also gives it a great position in this emerging ecosystem.