OK I may have went a little overboard on EEPROM 🙂 but it is very very useful. Some of you might think that EEPROM and flash memory is the same thing but you would be wrong. Have a look at this from webopedia

Pronounced double-ee-prom or e-e-prom, short for electrically erasableprogrammable read-only memory. EEPROM is a special type of PROM that can be erased by exposing it to an electrical charge. Like other types of PROM, EEPROM retains its contents even when the power is turned off. Also like other types of ROM, EEPROM is not as fast as RAM.

EEPROM is similar to flash memory (sometimes called flash EEPROM). The principal difference is that EEPROM requires data to be written or erased onebyte at a time whereas flash memory allows data to be written or erased inblocks. This makes flash memory faster.