How can you protect yourself when you don't even know who made the call? There are millions of people that use cell phones now, and a large percentage of them use them as their primary phone.
You may be wondering why you need a reverse look up of phone number. When you do this, the number will come up along with any others who may have the same name, and you can try to sort out which one it is that you are looking for. Imagine your mobile phone number being publicly available, you would be getting a million of calls everyday.
On the other hand, these are also used frequently in the research portion of the jobs of journalists and paralegals. When searching for a name in connection with a landline phone number, you may first want to try to use reverse directory information when searching. Mobile numbers on the other hand have to be collated manually, which costs the companies a lot in order to provide the service.
Luckily, it isn't expensive, and provides you with options. Always be responsible and safe.