Nickname of Myung-bak Lee, 17th president of South Korea. His last name Lee has the same phonetic as the number 2, hence 2MB. It is often used to show that he doesn't have enough capacity (2 mega bytes) to sustain in the modernized Korea.
2MB's brain capacity is 2MB while the every citizen has at least few Giga bytes.
If 2MB is a president, I'm Chuck Noirrs.