I’ve implemented Gravatar here, which means that when you post a comment you can have a small avatar appear next to it. Several sites now have them – Stupid Evil Bastard has had them for some time and Redemption in a Blog is toying with the idea.
They’re quite easy to implement – there are plugins for many blogging systems and Clagnut has some PHP code which is quite straightforward.
To have your Gravatar appear here, all you need to do is visit gravatar.com, create an account and upload an avatar to use. Then, when you comment on an entry, your gravatar will instantly appear. Providing you used the same email address before, it will also appear on older comments too (if you have changed email addresses, email me and I can fix old comments).
One note to TypeKey users: you will need to send an email address when commenting if you want to be able to use Gravatar. I have altered the sign-in link to require email addresses, however I have also created another link which doesn’t ask for them – make sure you click on the default one otherwise your Gravatar won’t appear.