Trust matters. As we study what makes our food system work, we find that enduring human relationships are the sinews that flex when the system is disrupted. Social media may be our new tool for building relationships, but speed may not replace our old, slow method of building trust.

Transactions based on trust make the food world go ’round. Food producers, processors, and distributors depend upon relationships built over time that result in trusted transactions and confidence in credit, quality, and consistency.

Long-term human networks that took much longer to build might be on the verge of being replaced or at least marginalized by our modern digital social networks. Our tweets and Facebook postings tend towards one-way communication, not two-way exchanges. Would you trust a new banker if the only way you could build trust with her was to receive her Tweets instead of meeting her for coffee?

Tom Standage, the author of A History of the World in 6 Glasses, and The Victorian Internet, just completed his latest historical hack of social media, Writing on the Wall: Social Media, the First 2,000 Years. It’s about time. Social media has been pleading for a historical accounting.

Standage posits that digital social media is similar to the old social networks in many ways. Short, informal messages have circulated for centuries, delivered via papyrus, paper, and in social settings such as coffee houses. Social exchanges became the underpinnings of business relationships and often led to trading practices that have endured until recent times.

Those concerned about the future of our food system are building mobile apps and big data assets with the intent to solve food supply problems through the Cloud. And they may be right. And in fact, we can see the benefits of digital farming already with improvements in precision agriculture and the improvements in resource sharing. But how will Twitter, Facebook, and LinkedIn build the trust so essential to trade and transactions? Will the speed and one-dimensionality of our modern social media provide enough depth to anchor the system during disruptions such as war and economic downturns? I’d guess that repeated handshakes that bring humans together in the same physical space matter more than repeated shout outs to your favorite supplier.