this is a really interesting thread in webmasterworld.com about how people use bad tactics while exchanging links, check the thread here,

webmasterworld.com/forum12/2036.htm

Bad webmaster! Bad...
Delink your links page
Bury the link to your
links page on a single page that takes about five clicks to get to
robots.txt
Run your outbounds through your cgi-bin counter script

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