Your commenter profile page is located here:
(Of course, you need to replace the "YOURUSERNAME" part with your Gizmodo username. Do keep in mind that your username may be different from your displayed username.)
You can also access it by clicking on your displayed username in the upper right hand corner of the site. (Keep in mind that you have to be logged in for your name to actually show up there.)
On this page you can see all your commenter activity—your comments, your replies, your private messages, and your friends. You can also use this page to change personal settings such as your contact email address (in case you forget your password and need to reset it) or your displayed username. You can even add a profile picture while playing with those settings—just click on the rather obviously titled "Edit my Profile" link and you'll see the option.
Other things to be found on your commenter profile page are options to change your password and your comment viewing settings using the—again, very obvious— "Settings" and "Change Password" links.