domain search shows a competitor?

[LittleEvilBunny]

Hi All,

I came across a very interesting Y puzzle. When I type in Y search my domain name but without "www." and ".com", Yahoo shows the first two results from my site (BTW, for some reason, the homepage is #2). There are some other websites below that mention my domain in their content AND among them a competitor's website homepage. When I click on the cached version of their homepage, there is NO mentioning of my domain.

How could this happen? Was I hijacked or do they have inbound links with my domain as an anchor text? How can this be investigated further?

Thanks.