Automattic Inc. is the company that has wordpress.com as a project and it also owns Gravatar. A gravatar, or globally recognized avatar, is quite simply an avatar image that follows you from weblog to weblog appearing beside your name when you comment on gravatar enabled sites (for example, on wordpress sites and sites with Haloscan).
Registering a gravatar costs nothing. It’s connected with the email address you use to register. You will receive a confirmation email including a link that will activate your account and allow you to set your password. To register a gravatar the image submitted must be 128 pixels by 128 pixels in size. When displayed it will be 80 x 80 pixels in size. Then when you input your email address and username on a gravatar enabled blog your little gravatar appears along with your comment.
Plugins are available from Gravatar for leading weblog software and there are tutorials as well. If you are comfortable editing theme files take note of Connor Wilson’s tutorial on how to setup Gravatars on your WordPress blog without the use of a plugin.
To request a gravatar from the servers, you simply add an image to your comments area with an “src” attribute that points to our gravatar image generator and includes an MD5 hash of the commenter’s email address. Since all gravatars are rated with an MPAA style rating, you can restrict your site to show only gravatars whose content you are comfortable with.
So what’s stopping you? Get your gravatar now.