Core Interaction Design
Design your platform around a single high-value interaction between producers and consumers
The Core Interaction Design framework provides a structured approach to building the foundational exchange that makes a platform valuable. Every successful platform begins with one core interaction that consistently generates high value for users. This interaction has three components: participants (producers and consumers), value units (the information exchanged that enables decisions), and filters (algorithmic tools that match the right value units to the right consumers).
The formula is: Participants + Value Unit + Filter = Core Interaction. For example, on Uber, the value unit is driver availability data (location, occupancy), the filter is the matching algorithm that pairs riders to nearby drivers, and the participants are riders and drivers. On YouTube, the value unit is the video, and the filter is the recommendation and search algorithm.
Platform designers must resist the urge to support multiple interactions from the start. Instead, they should perfect one core interaction before layering on additional ones. Facebook started with campus-based status updates before adding photos, groups, marketplace, and video. A valuable core interaction that is easy and enjoyable to engage in attracts participants and makes positive network effects possible.
- Every platform exists to facilitate one core interaction that creates value for all participants
- The value unit is the most critical element because platforms do not create it themselves; producers do
- Filters must ensure users receive only relevant value units or they will abandon the platform
- Perfect one interaction before expanding to additional ones
- The core interaction should be designed to be so attractive that it naturally pulls users in
- Identify Your Core InteractionDetermine the single exchange between producers and consumers that your platform will facilitate. Ask: what information, goods, or services will flow between the two sides? What decision does the consumer need to make, and what does the producer need to provide to enable that decision? For Airbnb, it is matching travelers with hosts. For LinkedIn, it is matching professionals with opportunities.
- Define the Value UnitSpecify the discrete packet of information that enables the interaction. This is what producers create and consumers evaluate. On eBay, it is the product listing with photos, description, and price. On Kickstarter, it is the project page with video, goals, and rewards. The quality and relevance of value units will determine whether your platform succeeds or fails.
- Design the FilterBuild the algorithmic mechanism that ensures the right value units reach the right consumers. This could be a search function, a recommendation engine, a news feed algorithm, or a matching system. A poorly designed filter floods users with irrelevant content. A well-designed filter creates the feeling that the platform understands the user's needs.
- Build Pull, Facilitate, and Match FunctionsEnsure your platform performs three key functions: pull (attract producers and consumers to the platform), facilitate (provide tools and rules that make interactions easy and valuable), and match (use information about each side to connect them in mutually rewarding ways). All three must work well for the platform to succeed.
- Create Feedback LoopsDesign mechanisms that generate a constant stream of self-reinforcing activity. When a value unit generates a response from a user, and that response creates more activity, you have a feedback loop. Facebook's news feed is a classic example: status updates generate likes and comments, which generate more updates. Effective feedback loops swell the network and enhance network effects.
When Sangeet Choudary led the launch of Fasal, a platform connecting Indian farmers with market buyers, the team had to carefully design the core interaction. They needed price data from local markets (mandis) as value units, and cell phones as the delivery mechanism. The hardest part was creating value units on the farmer side, requiring detailed crop information from people who had never used digital tools. They solved this by hiring local agents to help farmers create profiles and list their produce.
Parker, Van Alstyne, and Choudary developed this framework by studying dozens of successful and failed platform businesses. They observed that platforms like Google, Facebook, Uber, and Airbnb all succeeded by perfecting a single core interaction before expanding. The framework draws on the practical experience of Choudary launching Fasal, an agricultural platform in India, where figuring out the right value unit for rural farmers proved to be the decisive design challenge.