I can’t imagine that this stuff is cost-effective right now, but in a couple years? Damn, I might just buy me a Kindle 5. The writing bit could be handy, but its direct input method (just giving the magnetized powder a green light at point of contact, looks like) suggests to me that it may not be able to store that writing. Pure speculation on my part.
Details are few and far between, but I’m sure Bridgestone will out it when it’s good and ready for public consumption. Judging from the article’s limited statements, it looks like it may be Wacom-related as well?