Any given service - Grapevine, Vertex, etc - will have customers. For each customer, let’s assume on the order of 10^5 to 10^6 kind 30382 notes. Each note contains multiple WoT scores. Your service updates these notes periodically and stores them in a relay server. Different levels of service exist with higher levels of service meaning more notes per customer, more scores per note, more frequent updates.
Future: all of the above, but managed by a personalized WoT relay.