I've never used Waze. I tend to avoid using navigation maps altogether, much preferring to get lost. Here's yet another reason not to use navigation apps:

every time you tap that little "report" button, you're broadcasting your exact location, the precise time, and your username to anyone who knows where to look.

The username thing is a real bear, because apparently Waze ties your username to the report and makes it available to anyone who queries.

Waze caps results at 199 per query, so it seems like they're making some small effort to prevent someone from tracking a username as it moves acround a city. But as the person who wrote this article demonstrates, a little script gets around the caps quite nicely:

Instead of querying entire cities, I segmented them into hyperlocal geographic grids based on population density. Each grid cell covers roughly one million residents. Dense urban cores get smaller cells; sparse suburbs get larger ones.

The result? I'm capturing approximately 95% of all new alerts across every major city in 60 countries. Every few minutes. Around the clock.

Here's what that looks like visualized:

So now, if it so happens that somebody uses a username in Waze that is also a username they use on social media (who would do this?):

you can filter the historical data to see everywhere that user has submitted reports. Here's what that looks like for a single user over a three-day period in Amsterdam:

And remember: this user thought they were just helping other drivers avoid traffic.

If this data is coupled with other publicly available data sources (traffic cameras, vehicle registrations, voter roles, property tax records), it's probably not too difficult to learn quite a lot about a given Waze user.

The article goes on at some length about the horrible things one might do with such information.