No matter how smart you are, with the current Google algorithms, you can never run away from the possibility of your competitors destroying your presence on the Search Engines by using Google’s savvy algorithms against you. There are variety of ways, how your evil competitors can do this:
1. Google proxy hacking
2. Automated Comment spamming your website’s URL on explicit websites.
3. Automated directory submission of your website in **** directories (your ranking on Yahoo may jump but Google will surely bury you for links from such directories).