Last time I checked, Google had 2/3 of global search engine traffic.
So unless you are operating in a specific geographic space like
Korea or China where different market share applies, Google should
be the search engine you focus on.

I'm going to disagree. All that says is Google can deliver the most traffic. It doesn't say anything about the quality of the traffic. If your clients or customers are using Yahoo, Bing, and Ask more than Google…

From looking at my own stats I see Yahoo visitors to my site spend twice as much time and view twice as many ages as Google visitors. Ask visitors stay 6 times longer. Many more people visit from Google, but more doesn't mean better.

Of course I completely agree with your last point since good seo applies to all. I don't specifically target any search engine.

Originally Posted by TWD

But even that kind of misses the point.
Good SEO techniques are going to apply across the board
anyway.

That's the one thing I have always tried to get over to people, clients included.

As here

It should NEVER BE Search Engine anything. It should be Search Marketing and Search Optimising, because that is what you are actually doing.

Maybe it is a useful tools for marketing.But I still prefer google.

You can try whatever se you similar, but since yahoo search is learned by bing, and, the big G leads the se industry, I do not imagine you will benefit much from yahoo.

Of course you can, but do a detailed survey before deciding it.

Google is most used search engine at present movement. So working with google more easy then yahoo.

i think google is much stronger than yahoo

Ofcourse, but I highly suggest to aim for having site pages on the first page of Google before you target results from other search engines.

Hi)
so i have a question for you, why did you decide to use yahoo?
maybe you live in a specific region?
coz the desire is not enough...

It is better to try Yahoo even though you said that you are now using Google. Its better to open yourself to new ways of promoting your site