Here's why it's important to get listed in specialized directories.
When analyzing a dentist that was always showing up in the top ranking on Google for competitive keywords, I found that one of the main reasons is that he’s in important directories, including specialized directories which are authority sites. (He's in local directories and review sites too).
And he’s paying to be in those specialized directories. This is what sets him apart from others.
Think of it this way, you do the work once, you pay (some have one time fees while others have yearly and monthly fees) and you’ll get results over and over.
I don’t see those sites show up often in search results but it makes a huge difference for SEO. This is called annotations – you are mentioned in important places.
Below is a partial list of specialized directories to give you an idea of what they are.
You can find more specialized directories by googling your keyword, e.g. “directories of dentists” or “surgeon's directories.”
Samples of specialized directories:
Another article about local directories
Of course, you can also submit your site to free local directories and free specialized directories (if you find some).
When you submit yourself to a free or paid directory, make sure to add the full address with http:// (that’s what gives you the link).
Also, be consistent with the business name when submitting to directories.
Below are examples of local directories and specialized directories:
DENTAL DIRECTORIES (another example of specialized directories)
Dentists in San Diego, CA
101dentist.com/
They seem to collect data from other directories.
They mention “As with most other websites, we collect and use the data contained in log files.”