Whether in online or printed directories, reverse phone number look up service providers are a powerful tool for consumers. These databases allow users to research details regarding a phone’s owner by looking up the number itself, instead of the other way around. While usually utilized by police and emergency services to trace calls to their origin and provide aid, many websites and other providers have made this information available to the public.

One of the greatest benefits of reverse directory services is that they are a powerful weapon in defending consumers from telemarketers, scammers, fundraisers, debt collectors, crank callers or other undesired calls. In fact, recently, many community-based, socially-driven websites have arisen where users post their findings regarding phone numbers they have found to belong to known telemarketers and other businesses that make harassing phone calls. Many of these numbers are not to be found in normal reverse phone directories, and the website itself provides the service for free as a public service. Additionally, employers and business owners may use these directories to enforce company policies regarding employee phone use, recovering lost productivity and money.

These services are far from perfect, however. While many reverse phone lookup websites will give you very general information on any phone number – such as whether it is a landline or a cell and its general location—most require the user to pay a fee in order to obtain more useful information such as the actual name and address of the number’s owner. There is also no guarantee that a directory will have any information on the number being researched. One reason for this is that phone companies allow owners of landlines to pay a very small fee to have their numbers omitted from reverse phone number directories. Another reason that a number may not be found by a reverse phone lookup service is that no cell phones are legally allowed to be listed in any public or 411 directory.

The rationale behind this is that owners of personal mobile phones view their numbers as more private, secure, and personal, and that their rights to privacy outweigh the potential benefits described above. In fact, privacy is itself another disadvantage of some reverse lookup services. For a fee, some online providers will provide detailed personal information such as date of birth, address, income and even the value of their house.