Use this Who-am-I lookup page to see your IP address, your device's name, the port you are using, the referring website URL that brought you here, the browser name version and user agent you are using, and your physical location. All this information and more says a lot about who you are and is readily available to every website you visit.
"Who Am I" is similar to the "whois", the latter of which usually looks up information on a particular internet address or domain. This page is useful for reviewing information that you are distributing to the web about who you are when you visit web pages.
Rather than a truly inrospective look of yourself, this page displays how the web sees you. Your IP address is unique to you and can typically be used by anyone to pinpoint the ISP being used to access the internet and even a broad physical location. Your device's host name is sometimes literally the name you chose for your device for systems such as Windows, or often it is an auto-assigned name given to you by your ISP or otherwise.
Your port number is another essential aspect of determining the answer to the question "Who Am I?". It's one peice of a larger puzzle describing your technological access to the web. The referring website is pretty self explanatory, if you clicked a link to come here, it will display the web address of the page you clicked a link on, for example. You can also see your web browser details or use HTML5's geolocation feature to pinpint your location and display a map, which will answer "where am i" if not "who am I".