Some of the apps that are named in this research include, Angry Birds Classic, Flipboard, Audiobooks for Audible and a lot of games and beauty filters and that sort of thing.
Google says that they take this issue seriously and they have investigated this report.
They found some apps were violating policies and took action.
However, they didn't say which policies the apps were violating, or how many of them they found in violation, or what action they took against them.
There's not very much that users can do to stop apps from tracking them like this.
If you reset your advertising ID, then that kind of gives you a new identity with apps.
But if they're collecting these other identifiers that are called hardware IDs Those can't be reset.
So if advertisers have access to those, they can keep watching what you're doing with your apps and tracking you.
So this is actually something that app developers just have to refrain from doing or Google has to tell them to stop doing it.
So this is an example of a privacy measure that isn't actually protecting your privacy in the way it's intended to because other companies have found a way they get around it.
And that's happened before.
That just goes to show that even when you a have a privacy measure in place to protect you from having your data collected, they don't always work.