Differences in random number generators

I was playing AP last night, and some one wrote that the different poker sites have different random number generators. Now I am not saying that this affects your "luck", but is this true? I thought this type of program was pretty straight forward. I am pretty sure I was supposed to write one once in college, but I dropped the class.

My question is, are the sites different in how the random card orders are generated? Not that I think it makes difference in win/loss %, but just curious.