The problem.
Bloggers find Twitter very useful because it allows them to promote their blog and stay connected to other bloggers and their own audience. Because of Twitter’s popularity, why not illustrate comments with Twitter avatars instead of the normal gravatars?
The solution.
The first thing to do is get the functions file here.
Once you have that, unzip the archive to your hard drive, and then open the twittar.php file.
Select all of its content and paste it to your blog’s functions.php file.
The last thing to do is open your comments.php file and find the comments loop.
Paste the following line in the comments loop:
<?php twittar('45', 'default.png', '#e9e9e9', 'twitavatars', 1, 'G'); ?>
Code explanation.
Some months ago here at Smashing Magazine, an awesome plug-in named Twittar was released. Its purpose is to allow you to use Twitter avatars on your WordPress blog. Because of the number of requests I received from WpRecipes.com readers, I decided to turn the plug-in into a hack, for people who prefer hacks to plug-ins.
Of course, you could simply install the plug-in rather than insert its content into your function.php file. It’s up to you.