A reverse phone search through Whitepages.com often reveal the identity of an unknown caller. Whitepages also offers a caller ID app for smartphones that shows a caller's identity based on the phone number.
The White pages caller ID app can also block unknown numbers and spam and offers the ability to add photos from Facebook, LinkedIn and Twitter.
Searching for a number using reverse phone search requires typing in the full 10-digit number with area code. Unlisted numbers might not show up in the results. Those who are looking for someone using an old number should check whether the area code has changed.