Using hex coding of a page's content, some clever folks have found a way to make it appear that they had links coming directly from high-level authority sites. Dannomatic at Threadwatch points this out:

1. A series of pages are created on a domain say www.mylittlewebsite.com and the links point to a search request on one of these sites, example: copy the link url and paste to see what i mean, it's loooong
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2. Notice the formatting using HEX code when surrounded by a standard HREF tag this translates the link properly when the request is made to the authority websites POST for search – the result is properly translated into basic html. This is a clever coding exploit, this format ensures the request is properly formatted in basic HTML.
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3. Obviously the request is a negative search result on the authority website, however particularly site searches will cache all results of local searches, successful or otherwise.
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4. If these search results are spiderable content, then a robot such as Googlebot will view the cache results and see inbound links from a high profile authority site point to the domain in question.
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5. The result: www.mylittlewebsite.com jumps in the rankings.

I love seeing exploits and tricks like this talked about in the open. It lets a whitehat (greyhat?) like me see deeper into the brilliant minds of those who manipulate to achieve rankings - a fascinating pursuit.