E-Mail and Humor

E-Mail is a medium where communication is through words. This is just not the best medium to express emotions or use humor. The reason is because they don’t come across very well in an E-Mail. You may use emoticons to get over some of these shortcomings but there’s just no way to express tone, inflection, etc. Further, you will not be able to judge whether the recipient really understands that you are only joking. When you are having a conversation in person and happen to say something that the other person does not really appreciate, you can always say that you were only joking. This may not happen over E-Mail as never get to see the recipient's reaction, unless he or she writes back to say so. In that case, you can try and limit the damage already done.

So, the basic rule would be to avoid humor unless the recipient knows you well well enough to understand that you’re joking. It just is not worth the risk.