Now WordPress.com offers default avatars. You know that, you can use Gravatar (Globally Recognized Avatars) to display a cute picture of a commenter in your blog. Earlier you need to use some WordPress Plug-in or you need to edit the theme manually to support Gravatar, but WordPress 2.5 have a built in Gravatar support. You need to enable Gravatar in your blog (also you need a Gravatar Enabled WP theme).
Think of a situation where a commenter has no Gravatar picture. It means you need to give a default pic to the users who don’t have Gravatar.
WordPress.com has enabled this support and now they are offering six default gravatars.
(Settings -> Discussions)
Mystery Man – This is a common avatar we usually see until we upload our profile picture in community web sites.
Blank – No default Gravatar.
Gravatar Logo – As the title says, it will show a Gravatar logo.
Wavatar & Monster ID – These options will create some funny looking avatars. If your site is a professional site, then please don’t go for it.
Identicon – It’ll create some texture. WordPress.com is suggesting you to try this avatar. They also are going to use this avatar in their Dashboard.
Soon we can expect something similar to this in self hosted WordPress also.