My thinking was that if the other site could use our url in their title and have it show up instead of ours in a search, then anyone could do the same for any url. In which case, I would hold Alltheweb responsible for delivering the wrong pages. But then, I'm not sure exactly what's going on here. Hopefully, Brett will be able to enlighten me.
>>It sounds like you ran into an open proxy cache server<<
It's happened to us before. I found it by looking at link: pages via AltaVista. They were the only search engine that indexed these pages. I guess this happens, often. I was shocked when I first saw our site appearing under another URL.