Strange,would someone please explain this to me.

I did a search on my site www.singaporecampus.com for certain keywords.If searched under Yahoo regional categeory such as Singapore, the site appears in top 10 for certain keywords both in 'all web'as well as for Singapore only,but when repeated the same search for the same keywords on its search column under www.yahoo.com ,the site churns up an entirely different
result ! How and why does this happen?

Does this means different people from different regions gets different search reasults for Yahoo search for the same keywords ?