More and more websites and applications demand a sign-up to get access to content, bank account, e-mail or to be able to shop or to watch a movie. With time, registration processes became more and more standardized and a confirmation e-mail usually completed the sign-up with the validation of the user's e-mail.
A decade ago, this process worked quite well as users were using the Internet, checking their e-mails and registering to new applications on the same device and also in the same browser.
As usage pattern changed and users interoperate several devices with different browsers and different operating systems, usability challenges started to appear. This is because most authentication services are built in a way that sign-up processes have to be completed in the same environment. Operability between different devices and browsers was not anticipated and hence does still not work today. Consequently, starting on the smartphone and then opening the confirmation e-mail in a different browser of a different device will not complete a registration but rather lead to frustration for the user.