Some people pronounce the word 'data' as \'day tuh\, while others pronounce it \'dat uh\ (first syllable rhymes with 'cat'. Does anyone know what regional or occupational backgrounds lead a person to use one form or the other?

I have never heard the "cat" pronunciation, but in New Zealand, the most common pronunciation is dah-tuh, just to add to your list. I will be interested to see if there is a "right way" to pronounce this much abused plural.