If you want to do something to promote GNU-Linux / Ubuntu, you can add the following images (with or without link to an ubuntu webpage) to your e-mail signature:
Just copy and paste the code below and add it to your signature, if it accepts html code, and try it.
<a href="http://www.ubuntu.com/products/whatisubuntu/904features/"><img src="http://img233.yfrog.com/img233/7348/ubuntulogoformailen2.png" width="500" height="50"></a>
You could also say:
<a href="http://www.ubuntu.com/products/whatisubuntu/904features/"><img src="http://img145.yfrog.com/img145/7672/ubuntulogoformailes2.png" width="500" height="50"></a>
or build a similar thing for yourself:
"This mail has been sent without using privative software"
- another image
- another text
- another language
- link to somewhere else.
JUST DO IT AND USE IT!
Edit for GMAIL:
I had no problem inserting this html code in three different web mail sites. But, it is true, as of today, html code doesn't work in GMAIL's signatures. So this is what I did:
0. Build or download the image you want to use.
1. Go to Settings >Labs and enable:
“Canned Responses” feature
“Inserting Images” feature
2. Compose a new message
3. Click Canned Responses > New Canned Response
(call it “Signature-1” or whatever you like)
4. Edit your signature right there in the mail composer:
· insert the image in your hard disk by uploading it
· Select the image, press the link button and write the address (URL) you want it to point to.
(the problem with this is that you will have a rectangle around the image which you wiill not be able to get rid of)
· Add whatever else you want
5. Click Canned Responses > Save > [ ...and choose the signature name you gave it]
6. Get out the composing editor by clicking "compose" to compose a new test message that you will send to you.
Now you can quickly add your signature to any new e-mail or reply by clicking:
Canned Responses > Insert > [...Signature Name] (it will insert it right in the cursor's position)
Ideal! It even allows you to have as many signatures as you like.