Every Search Engine has points they give weight to , so for every of them you have to work specially.
Ranking on msn is easy cause their database is small and new sites can rank real high within days.But for google it takes time and even more time for yahoo (the oldest one

.
Imo if you have a site related to children and women you can get hits from msn , cause msn messenger has a huge sale and when installed the default homepage is
www.msn.com and generally people don't compare much and if they see a search box they enter the keyword and search. ( Pavlow

)
But if you have a tecnical site then msn is the worst cause engineers etc is conservative and they use what they tried , got the best results (google).
I have a tecnical site that ranks real good on msn and that brings me traffic as low as 10 uniques per month.
So target google and search for it.