Reviews, like many things, can be forces for good or for evil.
They can be used by competitors or just plain troublemakers to attack your reputation.
Or they can be used by you to help people find you online, and to get an idea of what great service and products you have.
Best you harness them for good.
Thanks to Google, it’s now easy to find out how you look in the universe of reviews. Just search on your company, product or service name, then click on “search options” and select “reviews” from the left column. It’ll bring up ONLY websites with reviews.
If other things than your company are showing up, just narrow the search using “” quote marks for an exact phrase match, add additional words or use “-” a minus sign for a negative search term (eliminate that from the results).
You’ll probably see such as the following:

Google Maps (Local)
Yahoo Local
Switchboard.com
YellowPages.com
SuperPages.com
RealPages.com

All of these are versions of online Yellow Pages. Depending on the business and locale you are in, you may see other sites as well.
Now the trick is to get happy customer / client / patient reviews added to these sites.
Check back from time to time and see how you are looking.
As your online reputation improves, watch your web traffic (and leads) increase!