If you make use of a signature, be it on e-mail, web forums or anything else, be courteous by following a few simple guidelines:

- Do not use an image in your signature, it slows down the page load time for everyone and detracts reader’s eyes from your message. This goes for both embedded and linked images.
- If your message body is smaller than the size of your signature, remove your signature.
- Do not include this message was scanned by [insert AV program] and is certified to be blah blah blah. People typically do not pay attention to this anyway, it looks very unprofessional and it adds to your message size (see above). Additionally, most everyone has their own AV anyway.
- Use a font color and style consistent with your message body. Again, you want people to read your text, not your signature.

Of course, you may disagree with some of the above, but exercise common sense and courtesy and consider what others see when reading your messages.