to what you&#x27;re saying - I would think jogging would be a prime example of &#x27;network&#x27; effect. If you head out to Beverly Hills, you don&#x27;t see anyone jogging except the dog walkers. But in certain parts of say, Hyderabad in India, the super-rich areas have massive number of &#x27;walkers&#x27; (even though the air is highly polluted and walking there is probably detrimental)