I was too young in '99. I don't think I knew what the internet was, besides I wasn't allowed to use computers, in fact I wonder if I could ever accessed Naruto in English back then.
But, I did watch Pokemon!
I don't think I'd heard of it in the early 2000s, but I did watch Digimon! And DBZ!
Nor do I think I knew about it in the mid 00s... back then I went to a boarding school, and wasn't really allowed to watch TV or use the net, but sometimes I did get to watch Yu-Gi-Oh!
So, 2007 (that's the earliest year that I can definitely say I knew about it). But, I only started watching the anime in 2010, even though I started watching anime in 2007 (Eureka Seven is still my favourite)