I understand the differences, however, the term was being used to describe EC2. In another example, I saw Amazon CEO Jeff Bezos in an interview refer to "grid

I understand the differences, however, the term was being used to describe EC2. In another example, I saw Amazon CEO Jeff Bezos in an interview refer to "grid computing" as a synonym for EC2 when describing it to a naive audience. Indeed the AMA authors comment about "setting the world on fire" was responding to the first announcement of EC2, not a general discussion of grid computing. He chose to use that term, rightly or wrongly, because like Bezos he saw it as synonymous with EC2.