For those who don't know, 'netiquette' is a term for internet etiquette. Essentially, it is a guideline for not being rude in your virtual encounters. Being in an industry (and world) that relies so heavily on electronic communication, netiquette is quite important. Recently at work, issues regarding netiquette have come up. I won't bother going into great detail, but here are a few helpful hints:
WRITING IN ALL CAPITALS means you are yelling. There's pretty much no way around this. No matter what you think you are achieving, the result is the same. The person reading your message will take it for boorish behaviour.
Writing in bold is only properly employed in very specific circumstances (say, headings or maybe an email signature). Interspersed in the body of an email will come off as insulting or impolite.
Underlining words and sentences in the body of a message does not, merely, emphasize your point, it makes you appear condescending (and, again, boorish).
Writing in a different font colour achieves the same thing as writing in bold and underlining.
WRITING IN ALL CAPS, IN BOLD, UNDERLINED, IN A DIFFERENT COLOUR is ill advised unless you are notifying everyone that we've moved to DEFCON 1. If you want to emphasize something, try italics, or just write it and assume that the person to whom you are writing isn't a complete idiot.