crespum: 

> Is embedded_io a no_std replacement for std::io?

yes 

> I don't see any details about embedded-hal-nb in the announcement

there's essentially no changes on the nb traits vs 0.2, other than moving them to a separate crate

> The post claims "SpiDevice trait now allows sharing a SPI bus between multiple devices". Didn't I2C bus have the same issue?

the 0.2 i2c trait did allow for sharing, you could impl it on a struct wrapping a Mutex/RefCell (this is what `shared-bus` does). spi didn't because the impl needs to manage the CS pin to allow sharing, which wasn't possible with the 0.2 spi traits (they were equivalent to the 1.0 SpiBus, ie no CS pin)