Difference between results in Google, Yahoo, Alexa

listed in google, aol,alexa but not in yahoo.com

[xMadx]

Hello,
I have 2 web sites, which rank #2 and #4 with key1 key2
My 1st site which rank #2 in google, rank #1 in AOL & ALEXA, but doesn't appear in Yahoo or in HotBot(using google option)
My second site have the same position in google, in AOL, Alexa, Yahoo, HotBot.

I use this syntax for my search:
[google.com...]

Why my 1st site doesn't appear in Yahoo?
How explain this difference?
What filter is used in Yahoo?
Both of my site are in english, located in the same server (different ip)

Thanks

[Winooski]

xMadx, I'm not up-to-date on the extent to which Yahoo!'s results differ from Google, but Yahoo! definitely does apply their own relevancy calculations. In other words, they choose to filter the results differently from Google, which explains why your site might appear in either one of the search engines but not the other. As far as the precise formula, that I don't know.

As for the HotBot question, no clue; so far I haven't been able to make either of them ("Google" HotBot vs. Google) display differing results. Anybody?