Which is your main search engine traffic source? Google or yahoo. For me its google. Even though Yahoo also indexes pages quite fast , but I notice that same page is rated high on google and it does not even feature on yahoo. Why is it so? I get around 1 Yahoo traffic for every 20 Google search hits.

Obviously it's because Yahoo is the second best. To make money as you should, use Google. Yahoo is great to supplement that stream of income. Don't ignore other possible streams of income, such as ad networks and shopping affiliate programs (Amazon would be a good example).

For INForum, the breakdown is:
Google - 77%
Live - 19%
Yahoo - 4%

Google resoundingly beats all of the other search engines.

Its quite surprising to see that Yahoo is on third position, Because I do not think many people use Live.com as their first choice of search engine unless, default Internet explorer settings.

I have always been a fan of google. Yahoo's position keeps on fluctuating but google is consistently at the first place for so many years.

Google is the obvious choice, I think. Its spiders fetch better and more relevant results. The algorithms are better updated. And Google Ad Sense program is great too.