I was going to mention SEO and use the example of googling for "click here", but I was surprised how the wikipedia article on the phenomenon in the OP ("Mystery meat navigation"[1]) actually managed to make it to #3, amidst downloads for Acrobat Reader, QuickTime, Java runtime etc. How did Google manage that? I'm impressed.
[1] http://en.wikipedia.org/wiki/Mystery_meat_navigation