Most people are used to the idea of published phone directories, and some expect similar directories to exist for email addresses. In fact, most email providers own and maintain the records themselves, and only allow them to be searched by reverse email search services. Like cell phone directories, email directories are considered private, and usually charge a small fee to access, but depending on your email provider you might be able to find out some things using a free email lookup.

The main reason that email providers do not publish directories because aside from security concerns, comes the sheer difficulty of doing so with any real accuracy. Everyday people change their email address, and more domain names are created to accommodate the popularity of this communication medium. Even if this data was published online, it would still be nearly impossible to keep it completely updated.

Of course, email providers update their own directory records constantly, because it is vital that the company always has a good idea of how many email addresses exist at a given domain name, and which of these accounts are still active. This means that just because this data is not public, does not mean you cannot get access to it. This is where reverse email searches, and even free email lookups come in.

Reverse email searches are an important tool when searching an email address, and can return information about not only the domain name, but also the name of the person who owns the account, as well as their computer's IP address and internet service address. Even a free email lookup can tell you some valuable information, including the location and IP address of your email provider. In many cases, this is a valuable clue to the occupation and location of the person you are looking for.