An X-Face: header allows you to include a 48x48 bitmap (one bit per pixel) icon in the headers of your e-mails or Usenet news posts. Some e-mail and news clients can display these icons along with your message.
Now Fidolook allow to include X-Face: header to your messages which allow to introduce an identity and eccentricity to your messages.
More info about X-Face and converter for creating X-Face data from your pictures you can find at
http://www.dairiki.org/xface/