This is a most excellent place for technology news and articles.
Ads aren't why you should be concerned about apps w/ microphone access...
Where exactly are you getting the idea that this belief is widespread?
Not my title, as I already said. But anecdata backs this up ime. Go ask your parents for a giggle, see what they say
I don't either hut the alternative is much worst in my opinion. It would mean the algorithms are so advanced they are predicting conversations instead of listening to them.
Two ways to process voice, on device or on server. Device-based solutions either are very basic and just detect differences between words or need training data based on your voice or they need lots of processing power for more generalized voice recognition. So is your battery draining and phone is often hot because an app is keeping the mic on and keeping the phone from slowing the processor? Other option is to stream the data to the server. This would also increase battery usage as the phone can't sleep, but might not be as noticeable, but more evident would be your phone using a lot more bandwidth than is reasonable while you aren't actively using it.
I'm always torn on this topic because, yeah there's hundreds of biases that can be attributed to this phenominon.
IE something becomes a popular topic in your area. Meaning more people in the area start searching the topic in that area, thus advertisers start pushing it to that location.
Obviously ads are also tracking you in 100 ways on what you've searched for, looked at etc... which means it could have a good guess of what you are going to talk about, before you do.
But at the same time, I think everyone can think of a lot of stories of things that just seemed to perfect, to out of the blue. For me the big one was 10 years ago when I walked into an attic, said "man it's fucking dark up here", opened my phone, and a big ad for a flashlight app popped up.
