Why are Duplicates So Bad?
The biggest problem with duplicate listings is that they tend to spread ranking data in the form of reviews, citations, pictures, and user generated content across the different duplicate listings. So, instead of having one strong listing you end up with a couple mediocre listings that will struggle to rank.
Just recently, I had a client who had worked hard for some solid reviews and citations drop from the 7 pack because of a duplicate where a lot of data transferred to the new listing.
How to Avoid Duplicates?
I want to keep this as simple as stupidly possible. Make sure that your Business Name, Address, and Phone number (NAP) are exactly the same everywhere online. This is the golden rule of local search. The big secret to success. So, go get to work and if you are interesting in more local search talk then follow me on twitter.
by Mike Ramsey | Nifty Marketing
Read the entire article at Search Engine Journal: 3 Major Causes of Duplicate Listings in Local Search