identity and social graph is imo a great bet for blockchain powered use cases to reach mainstream adoption.
Becoming the home of blockchain social apps, enabling the easy integration of the social graph within every single app, connecting billions 
of people. Shopping with friends, service/restaurant/bar/… reviews from friends, discovering places with friends, gaming with friends, … is the value proposition of web3 social and a decentralised social graph.
Connect once experience everywhere.
Key metrics to track and optimise for is DAU.
V in TVL stands for connections and certificates, identities, resumes, …