Kif Leswing, CNBC:

More than 45,000 people have signed up for Utah’s contact tracing app, Healthy Together, since it was released in late April, the app’s developers told CNBC. That represents about 2% of the state’s population, but could still be helpful to the state’s health department as they attempt to track and notify people who might have been exposed.

And:

Healthy Together was built by Twenty, a social media start-up that previously built an app that helps young people meet up in person. After the pandemic started, the state of Utah reached out to the company, the founders said. With their staff of about 50 employees, they repurposed their social media-oriented technology for contact tracing in three weeks.

Privacy? No. Here’s how it works:

“Jeff and Sarah are two individuals in this example who don’t know each other but they both have the app on their phones. And so the both phones are emitting Bluetooth and GPS signals,” Allgood said. “Through that data we can identify whether or not two people have spent some time together.”

Here’s the costs involved:

Utah’s governor’s office spent $2.75 million for the app and other improvements, and will pay $300,000 per month in maintenance fees, according to public records cited by Utahpolicy.com, a website focusing on local politics.

One issue I struggle with, no matter the approach, is adoption. If few people (2% of the population, in Utah’s case) sign up for the app (fair to assume even fewer actually use the app?), can it still be effective?

And with all that juicy data out there, how long until that data finds its way into other hands, hands without the public good at heart?

The user also has a choice to share their location data with the public health department if they test positive, and any Bluetooth or GPS data is deleted after 30 days, Twenty said.

Good to know.