Adding comment avatars to your blog is a great way to quickly recognize comment authors and distinguish same name commenters. It also bring a community vibe to your blog. Here’s an example:
Although there’s no one central avatar system, fortunately, there’s practically a plugin for every avatar system. Pick the system you prefer, download the matching plugin, and then install and integrate the plugin to start displaying avatars with comments.
Currently, Wpdesigner is using the MyAvatars plugin to integrate avatars from MyBlogLog. For the longtime Gravatar users, there are several available plugins. For examples: WP Gravatar and Gravatar 2.
Of course, no one external avatar system will catch all commenters. No worries, there’s a localized avatar plugin that allows your users to upload their own avatar. You then decide which factor to recognize the commenters by (name, email, etc.), in order to assign the uploaded avatars.