This blog explains it better than I can: http://picturesofpeoplescanningqrcodes.tumblr.com/

Nest uses it as part of their application setup process for Nest Protect. Of course, it's completely broken because their app doesn't bother to focus the camera while trying to read the QR code. So then you have to enter the code manually into their app, which is also broken because they use a font that doesn't distinguish between 1 and l, which just magnifies their initial error of using codes that include 1 or l.

I've had an iPhone for 5 years, an android 3 years before that, and I still have no idea how I'm supposed to scan a QR code. Does any arbitrary QR reader app work for every QR code? Is QR scanning natively supported in any way?

> Does any arbitrary QR reader app work for every QR code?

Yes, basically.

> Is QR scanning natively supported in any way?

No idea for every phone, but not native to Android or IOS AFAIK. Probably Google Goggles, but that's not built-in usually. We recommend FreeOTP for MFA at Userify[1] (plug: SSH key management) which has a built-in QR code scanner/reader, but Google Authenticator needs a specific third-party (and permission-greedy) app.

1. https://userify.com

I also use FreeOTP, but be aware that it stores the keys in plaintext.

That was the reason I chose it actually - it gives me a way to encrypt and back up my codes in one fell swoop - but it is definitely a risk to be aware of on a rooted device.

It's natively built into Windows 10 (for certain less technical descriptions of "native"), but you'll have to ask Cortana if anyone knows that, much less knows how use that.

Yeah, the use cases are pretty slim. Link to your app on a flyer or in a location I'm going to be interested in it is the one use case for QR codes I might have used multiple times, but in general that also is a sign of the inability to create a nice short-link instead.

Sometimes the apps are useful for barcodes that are already there: I sometimes scanned ISBN codes on books that look interesting in the library or in stores, and used book sellers have apps where you simply scan the books you want to sell and get the price.

All in all, QR codes scanned with a phone are not that much nicer than typing something to be that valuable, even if you've found something I actually want to interact with. Start the app, find a position where the code is in the frame and the camera can focus, wait to focus, wait to decode the code and display the result, do something with it... takes quite a while as well. Normal barcode applications work so well because the scanning hardware/process is fast.

Here in Finland invoices have QR codes. You can set up a payment automatically on the due date through a your bank's mobile app. This is probably the only time I've actually scanned one.

I've seen QR code being read when people access WhatsApp through it's web client. I haven't seen other successful use cases as such.

I've done this, and used them for Google Authenticator.

I work on an Open Studio Event for artists. We wanted to see if people used the QR codes we put on posters etc, so we linked to a different landing page (mobile friendly).

Very very few did use them. Probably not worth the printed space.