Digital game sites have been allowing you to download your purchased games across multiple devices for literally a decade. Cross-platform stuff too, although that's a bit more recent.
Nintendo should have had it ready for the Wii. The fact that they not only missed the Wii, but the 3DS and Wii U is beyond belief.
Joe thinks the new advancements in Web and App development are a fad though. Maybe cross-platform purchases are too?