this is an interesting question. hope someone can give some tips of this one.

I don't think there is any difference in promoting your website in Google or Yahoo. In both Search Engines the key factors are:

1. Quality unique content

2. Quality backlinks

In Yahoo a little bit keyword spam works

are either of these more important than the other? is it essentially like having 2 different sites that you are promoting due to the different requirements of each?

better to aim for better "long tail " key words. Going for a single word is a bit like trying to shoot one fish in particular, in a small pond that is jamed packed. "iphone" would be a nightmare to rank highly for. " iphone shop " would be easier but " iphone shop alabama " well that would be easy. I could get a number one page listing for that term inside 48 hours!! I am no expert but I have held number one spot in google and yahoo for certain key word terms, for over 10 years. What is the nature of your website ? maybe I can help.

I just took a look at your profile searchbliss, "Search engine Optimizer" for how long ?