NAP is short for your business name, address and phone number. When Google scans various databases on the internet for your company it's absolutely crucial that these three items are EXACT and consistent. If I was on Yelp as "Brian Houdek The Web Designer" or "Brian Houdek Web Design LLC" or "Brian Houdek Web Design Inc" Google would look at that as a completely different company than "Brian Houdek Web Design". If your address is "123 Test St" it's crucial you write it exactly the same throughout the internet. "123 Test St." (dot after St.) or "123 Test Street" will be looked at as different and therefore not the same company. Finally, your phone number must remain consistent. Did your number change over the years? Do you have a local number and an 800 number? Make sure you always pick one primary phone number and always enter that phone number as the primary one.
The more LEGITIMATE databases your company information is in the better for SEO (Search Engine Optimization). These directories give your business validity in the eyes of Google. Most of them link back to your website, which is another ranking factor Google uses. As a rule of thumb, I recommend my clients use their Google My Business listing as the "master" listing, ensuring all other listings have the same information.
On the Internet there are four major data aggregators that store your business information. These are Neustar Localeze, InfoUSA, Acxiom and Factual. These data aggregators take your business information and push it out to many smaller databases on the Internet. In addition to these aggregators, there are also many big name directories your business should be in. Examples are Bing Places For Business, Apple Maps, Angie's List, Manta and many, many more.
I have multiple tools to scan these databases and see where your business information is missing or inaccurate. I can easily update this information and charge a flat fee. If you want me to run a free scan for your business contact me today.