I don't know of anyone in the USA who has used these apps. They never really took off. Since they rely on a "network effect" to be useful... even if you install

I don't know of anyone in the USA who has used these apps. They never really took off. Since they rely on a "network effect" to be useful... even if you installed one, few people you came in range of would have it installed. https://apnews.com/article/us-news-smartphones-coronavirus-pandemic-district-of-columbia-20aa29d9d018597e2e464128b529e928 https://apnews.com/article/us-news-smartphones-coronavirus-p...