Oh ye mighty introverts, the reason that I've posted this somewhat garish, yet memorable image is because it's memorable.
If you're going to participate in social media, a memorable avatar is a must-have. You might want one prettier or less odd than this one, but trust me, you need one!
I used to use a comic book character image, but after deciding that I didn't want to be using someone else's copywrited material, I got my friend Scott Marshall to create this for me.
The avatar is a part of that whole branding process, like creating a logo, motto, theme, or whatever. The avatar helps people recognize your work during a quick scan (and a lot of people are quickly scanning web pages for interesting content.)
Whenever you sign up for instant messaging, social media, social news, social bookmarking, or some other kind of site that allows you to use an avatar or photo, do it! It will give you a bit of an edge over other contributors who don't use them. It's a way to sell yourself without some of the face-to-face interaction that introverts don't always enjoy, plus you can do it from the comfort of your home.
You don't need to create a special image like this. You can use your own photo (note: I don't really have blue skin or a glowing green exposed brain....) or a clever image of some other kind.
I had my friend create this avatar because it seemed to go well with (start plug) my other blog, The Uncanny Broadcasting Brain Blog (end plug).
Let me know what you come up with!
EDIT: one other quick note: consider having several versions of your avatar at different sizes. I have 50 by 50, 128 by 128, and 400 by 400. Different sizes will look and fit better depending on the website that you are using.