FYB isn't really my cup of tea either (my attention span is too short) but that doesn't mean it's a bad site by any means. If the information is solid and the explanations/demonstrations are clear, motivated players will be able to learn from it. It's a matter of preference more than anything I think.
Of course most online instruction is geared towards us low/intermediate level players. We're the biggest market, and we have the most to gain from seeing someone explain and demonstrate how to play. It's the same thing with books--the vast majority of tennis books that I've run across seem intended for lower-level players.
I think it's wrong to say that the only good instruction on the web comes Salzenstein and Yandell. Just off the top of my head there's Tae Byon, Heath Waters, Mauro and Kyril at the Tennis Vault, Cristophe Delavaut-- and there seem to be some great videos at tennisresources.com as well. I'm sure I'm missing some.
Last edited by Avles; 11-28-2012 at 04:36 AM.