SPI Flash capacity and speed

bratan:
So please forgive my n00bness but I'm a little confused about capacity specs of flash. It seems to be specified in Megabits, not megabytes. I thought Megabits were reserved for measurement of speed not capacity?

Memory chips can be specified as bits, bytes or whatever (many early DRAM chips where bit-wide so bits was natural).
Bytes is universal for packaged storage devices like discs, USB sticks, CDroms, because at that level no one is interested
in how the data is stored.

For comms bits or baud are mainly used for actual wire-protocols (like ethernet), but when talking about bus interfaces to mass-storage,
bytes tends to be more common (talking about disc write speeds, for example)