There's a reason, of course -- the current e-ink technology is simply not built for webbrowsing -- the page refreshes a lot during scrolling, images don't look great and in the case of the Kobo, there's no pinch-to-zoom, so you've got to rely on an ever-present slider on the bottom to make things larger.
In real-time bidding, as soon as a user visits a Webpage, the visit is auctioned to the highest bidder, based on attributes such as the type of page visited or previous Webbrowsing by the user.