It's not good to send others inappropriate pictures or e-mails. Why, because you can get your self into trouble and it won't be that nice to get into trouble for a picture or e-mail.
Don't send chain letters, and jokes. Becasue you can get another person scared also you could get into trouble with that persons parents.
Read an e-mail before sending. Because if you don't and your mad then it's not fair to take it out on another person..
Don't send an e-mail with all caps. Why becasue it sounds like your mad at that person that didn't do anything to you.
Make a conversation personal. Because you dont want others to know what your talking about with another person