Ranked in Google but not Yahoo or Bing
 

For a few of my sites I'm ranked really well in google, some even 1st position but I can't find any results on Yahoo or Bing. Does anyone know why that might be?

I thought all search engines worked in the same way

as far as i know it's about there algorithms in think they are different, it's funny when my site was very new it ranked well in both bing and yahoo 1st page for four keyword terms
now it's pretty much nowhere. But for google now 1st page for 8 to 10 keywords

Google Is Best Forever In Ranking