Youtube is so full of idiots singing the Pokemon theme tune that I couldn't find the obvious clip I should have here. So here's one the Japanese themes and openings.
1998: The Year Anime Broke
Pokemon pretty much broke anime in the English speaking world, so bow down and worship your electric yellow mouse master. Sure there'd been other popular cartoons from Japan, but the difference here was that this was a multimedia blitz that didn't hide from you the fact the show was from Japan (even if the actually adaptation might have done on occasion). And it was such a massive success that TV channels started to want to fill their schedules with similar shows. When I was the age of the target audience for Pokemon, I certainly watched shows animated in Japan, but there was never news articles about “Battle Of The Planets – The Latest Fad From Japan!”.
I am going to go out on a limb and declare that Ant and Dec dressed as Gary and Misty on SMTV was the point when anime became mainstream in the UK. In fact I wonder if they hadn't embraced it as a core part of that hugely popular kids show that maybe you wouldn't have got the other channels looking to pick up more US (and occasionally Australian) dubbed anime shows.
1998 is a lot of people's anime year zero in the UK and US because of Pokemon.
As fads tend to peak at 3 years and fade after 7 (hello TMNT!) 4kids were wise to pick Yu-Gi-Oh in 2001 which has had the effect prolongng the mainstream attention to anime. There's been a long gap however for the next mainstream hit to appear (hello Naruto!) which is probably a major factor in the stagnation of the anime market.
However in about 7 years time I fully expect us to get a retro revival of Pokemon just like we had for Masters of The Universe etc.