Social Media Finder uses a data source of PeopleGraph which is a service of Dunn and Bradstreet.  PeopleGraph scrapes various social media services based on email addresses it has on file in order to catalog social media accounts owned.

Results are returned based on PeopleGraphs ability to scan accounts.

If there is a person whom you know has a social media account, but isn't returned by Social Media Finder, it's likely because the owner of the account has privacy settings engaged.

Take Facebook for instance.  Below is a screen capture from Facebook's privacy settings: https://www.facebook.com/settings?tab=privacy:

User-added image

The above settings mean that
  1. Only Friends of Friends can look up this account via my personal email address
    • This means if I am friends with Stephen Colbert, and Stephen is friends with Jimmy Kimmell, then Jimmy can look me up by my email address and find me
    • If Stephen is NOT friends with Jimmy Fallon, then Jimmy CAN NOT look me up by my email address.
  2. Anyone who has the account holder's phone number can look the account holder, but since PeopleGraph doesn't look up according to phone number, no result would be returned for it.
  3. Search Engines and data scrapers cannot link to the Facebook timeline for this account
The information returned by Social Media Finder is dependent on ability to see a person’s social media content which is controlled by the owner of the social media account.  Social Media Finder cannot override the privacy settings of individual social media account holders.  

Note: We provide links and information about third-party websites in an effort to help you resolve issues and answer questions. We are not responsible for the information on third-party websites, and we cannot assist in implementing solution on these websites.