Has anyone heard of or used this app?  Read somewhere that it will identify the real account holder of cell phone (not all but many).  

I just looked at in the Apple App store and read the description and (mostly older) reviews.  

 
I don't see this doing anything that you can't already do with your current phone capabilities. And it looks like the potentially useful functions to proactively block spam calls requires a monthly fee.    

 
They claim to have an extensive database of "actual" phone number owners. The idea is that when your phone says "Bob Smith" is calling, it's really a call center of fraudsters - like the calls I get from "Visa" telling me I qualify for a lower rate.  Total BS scam to get my card number and PII.  But I suspect the so-called database is limited to the numbers flagged by their users, or the same publicly available info your phone service provider already uses to show you the callers' name on an incoming call.    

 
I suggest you pass.  

 
Life is good

 
The Cat