https://www.techdirt.com/articles/20200513/06192044488/everyone-agrees-that-contact-tracing-apps-are-key-to-bringing-covid-19-under-control-iceland-has-tried-them-isnt-so-sure.shtml

Given the massive impact that the coronavirus is having on life and the economy around the world, it's no wonder that governments are desperately searching for ways to bring the disease under control. One popular option is to use Bluetooth-based contact tracing apps on smartphones to find out who might be at risk from people nearby who are already infected. Dozens of countries are taking this route. Such is the evident utility of this approach, that even rivals like Apple and Google are willing to work together on a contact tracing app framework to help the battle against the disease. Although it's great to see all this public-spirited activity in the tech world, there's a slight problem with this approach: nobody knows whether it will actually help.

That makes the early experience of Iceland in using contact tracing apps invaluable. An article in the MIT Technology Review notes that Iceland released its Rakning C-19 app in early April, and persuaded 38% of Iceland's population of 364,000 population to download it. Here's what this nation found in its pioneering use of a tracing app: