If manufacturers want folks to be able to capture a constant stream of biometric data, they have to solve two fundamental problems.
That people will be able to/want to wear it all the time. That means elegant enough to wear with cufflinks, but unwieldy enough to wear to the gym.
Recharging without taking it off. This is always going to be the biggest problem. As soon as it’s not on your wrist, it’s not collecting data. And when it’s not on your wrist, it’s less useful than your phone.
The trouble with many applications and websites is that they are optimised for widgets and controls, not typography. Reading comprehension is tied directly to the number of words on a line, the paragraph spacing, and so on.
1910 takes a look at solving that problem for email.