As of November 8th 2016, the database seems not available. Error message "The user was not authorized".

Thank you for your feedback! yes, you are right in both cases.

I have updated the article and sent it for publishing. Hopefully, it will be corrected in 2-4 days.

Windows phone and iPhone

Thanks Stan. I have downloaded and run the code from the link you shared ("Just launched new open source project QrCode.Net at http://qrcodenet.codeplex.com").

The QR codes seem to work,...

Thanks a lot Stan. I got the same results with your image so far. The phone cannot read it.

Other QR codes from the web seem OK to phones, I wonder...

Thanks Stan for clarifying. I agree with you, it is worth investigating 🙂

So far, we know that the QR codes created with the tools in this article are not compatible...

After trying the code, the images generated seem unreadable by a cell phone. Is that expected somehow?

The online code reader at zxing does recognize it, but iPhone or Lumia phones...