Here are a few sites to help you contribute your highly esteemed opinions about existing businesses.

Naymz.com - Sign-up and invite your invite people to write reviews about you and your work.
Rapleaf.com - Look up your reputation, rate others, and they will be invited to rate you in return.
RepVine - Reference and reputation management combined.
ReputationDefender.com - A service that attempts to help you get things being said online about you removed
TrustPl.us - An online reputation service that ranks based on trust scores.
Monitor This allows you to monitor and track keywords over multiple search engines.
Keotag.com A service that allow you to search for tagged blog posts across multiple blog search engines.