Bike2 has built a chainless electric bike motor that it hopes will become a major part of bicycle manufacturing moving forward. The chainless e-drive system will allow manufacturers (at whom it's targeted) to outfit standard bicycles with an electric motor that can be recharged as the user pedals.
What Bike2 hasn't discussed is what happens when your bike runs out of juice. It's fully electric, so there's no way to manually pedal like you would with a chain-drive bike. Does it turn into a stationary bike until you manually recharge it by pedaling? Do you need to carry a portable battery charger just in case? Are you going to end up in a Starbucks looking for an outlet to charge your bike like everyone I know who has an electric skateboard does?
There are a lot of questions here, but the idea is nonetheless intriguing. And no more issues with broken chains should make everyone excited for the future.