Interactions with physical resources sometimes leave traces or other evidence. Many of these traces are unintentional, like fingerprints, a coffee cup stain on a newspaper, or the erosion on a shortcut path across a lawn. Fans of Sherlock Holmes and CSI know that clever forensic investigators can use these residues of interactions to identify or vindicate suspects. Other interaction traces are intentional, like a student’s yellow highlighting or notes in a textbook or spray-painted graffiti on a building. But not every interaction leaves a trace, traces fade over time, and different traces associated with the same resource lack consistency. This means that most traces are not of much use.
However, when Organizing Systems contain digital resources, or physical resources that have sensing, recording, or communication capabilities, interaction traces can be made predictable, persistent, and consistent. Each record of a user choice in accessing, browsing, buying, highlighting, linking, and other interactions then becomes an “interaction resource” that can be analyzed to reorganize the resource collection or otherwise influence subsequent interactions with the primary resources.
Interaction resources are often essential pieces of information that make Organizing Systems function. Most human toll-takers have been replaced by smart “toll tags” that broadcast their identity when the car they are in passes a radio receiver at a tolling location. Each interaction resource created identifies an account and credit card with which to pay the toll; taken together, the collection of these interaction resources can be used as the primary resources in other Organizing Systems that manage traffic congestion, or that support road design. Similarly, interaction resources created by search engines can be used to adjust the order of search hits, select ads, or personalize the content of web pages.