8 is considered a lucky number by many, as it is often associated with positive attributes. When on its side, 8 becomes a symbol of infinity, therefore having its association with longevity and strength. 
For this reason, 08/08/08 is probably considered the most  popular date this year, and probably in this century. It is considered an auspicious day, especially in Chinese culture, as the number “8”  when pronounced in Mandarin or Cantonese, sounds like the word “prosperity”, symbolizing wealth and luck.