It can be especially annoying when you receive repeated calls from the same number. You may not want to answer a call from an unidentified caller, but at the same time you may be very curious about who is being so persistent about getting a hold of you.

There are other reverse lookup services, but they can be quite costly. For example, the Intelius reverse phone number lookup claims to be free, and it will conduct the search for free--but if you actually want to see the relevant information it will cost you $5.Whitepages.com will also do a reverse lookup search for "free", but charges $2 if you want to have the name associated with the reverse lookup texted to your mobile phone.

There are also . In the Apple App Store, there is another free app called EveryCall Reverse Phone Lookup, but judging by the user ratings--with 308 ratings registered it has an average score of only 1.5 stars--the app is not very functional.There is also an app called Mr. Number which has a much more respectable 3.5 star average rating, but costs 99 cents for 20 lookups, then an additional 99 cents for each subsequent set of 20 lookups.

You might be familiar with BeenVerified from the service and app. The Background Check app performs a comprehensive search of public records and publicly available information to a conduct a background check using a name or e-mail address. BeenVerified.com also makes an app called Sex Offender tracker that again uses public record data to identify registered sex offenders in proximity to your current location.

I asked Ross Cohen, Director of Business Development for BeenVerified, what drove development of Number Guru. Cohen explained that it has always been the goal of BeenVerified.com to make public record information affordable and accessible to everyone. "We felt the best long term strategy for us and our Number Guru users was to make the service 100 percent free and create some disruption within the current market."