There's been a lot of confusion over 1024 vs 1000,
kbyte vs kbit, and the capitalization for each.
Here, at last, is a single, definitive standard:
[[table of various kinds of kilobytes]]
SYMBOL | NAME | SIZE | NOTES
kB | Kilobyte | 1024 bytes OR 1000 bytes | 1000 bytes during leap years, 1024 otherwise
KB | Kelly-Bootle standard unit | 1012 bytes | compromise between 1000 and 1024 bytes
KiB | Imaginary kilobyte | 1024 sqrt(-1) bytes | used in quantum computing
kb | Intel kilobyte | 1023.937528 bytes | calculated on Pentium F.P.U.
Kb | Drivemaker's kilobyte | currently 908 bytes | shrinks by 4 bytes each year for marketing reasons
KBa | Baker's kilobyte | 1152 bytes | 9 bits to the byte since you're such a good customer
{{alt text:  I would take 'kibibyte' more seriously if it didn't sound so much like 'Kibbles N Bits'.}}