Here's how it's being done:
They return results as mysearch.html
where "mysearch" is the search terms you used.
If you download that "file", it contains a browser re-direct to "www.search-fu.com" and nothing else.
Being smart, I entered just the site name into the browser by hand.
It then re-directed me the ebay.com search page with the search terms entered IN THE URL same as "mysearch" !!!
How was this done when I didn't let it automatically re-direct me with the downloaded file?

The search-fu site had my IP LOGGED !! Plus they logged my search terms so they can enter them into the ebay search page.
I say it's SPAM and ebay is paying search-fu to do this, so they are responsible.
I tested the IP log part by logging in again to my ISP, thus getting a different IP address and then I only get redirected to ebay without the search terms.

Time to write ebay and get this stopped!! It's SPAM !!