crobb305 - 12:31 pm on May 18, 2012 (gmt 0)
The minus sign before a keyword excludes any result with that term. So you will see serps without that, and consequently your site will seem 'to rise' in the serps.
See also:[support.google.com ]
This particular phenomenon has nothing to do with excluding phrases that exist on the site. That's what is baffling about it. You can make up a domain, with any word, say supercalifragilisticexpialidocious.tld and it will still work. I guarantee that word isn't on my site.