What is an IP address?
An IP (Internet Protocol) address is the numerical representation of a computer's physical location. This data is assigned by Internet Service Providers in order to actively monitor their customers. With the help of the IP address, they can control the bandwidth and other services their clients demand. Since it represents the physical location of the connected device, the IP address could be used to locate the exact location of the computer. The IP address is divided into four parts separated by dots (e.g. 192.168.0.1).
This data is useful in many ways and the internet service provider is not the only one taking advantage of the information provided by the IP address. Webmasters use the information to learn more about their visitors. By determining the location of those who visit their site, they can tailor the online content to the preferences of their visitors. For example, online stores can change their product line based on the popular items in that area or a blogger would focus on topics interesting to their visitors based on their location.
But aside from webmasters and ISPs, IP addresses are also used for tracing an email. Before any message is sent, the ISP extracts the IP address of the sender. This is a requirement for every email sent for security purposes. The IP address is stored in the email header and advanced users can easily extract this information from their email. Most (if not all) email providers provide step-by-step instructions on how to access the email header. If you can find the email header, you can also extract the IP address.
Tracing the physical source of the email through IP address has many advantages. This small data could be used to determine if the message came from a reliable source. Some even use this data to trace the source of a threatening message. It's practically a data that can help in online safety and data accuracy.