Honda, Yamaha, KTM and Piaggio have signed on thus far, and the group has left an open invitation for other manufacturers to get on board with the initiative.
Range and charging times are still bugbears for electric motorcycles, which can't carry the huge battery packs that electric cars can. This initiative is unlikely to result in a system that's capable of taking riders out touring; batteries offering hundred-mile ranges at highway or sport riding speeds will be too heavy to lift out and swap, and running multiple modules would add packaging bulk and weight.
Instead, it'll likely prove very handy for smaller commuting bikes and scooters, giving people that don't have a dedicated charge point at home or the office a simple and quick way of powering up. And it'll be handy in the off-road segment too, where electric dirt bikes can be kept light and fun with smaller swappable batteries to keep them out on the trails or the MX park all day.