I’ve put this on some of my syllabi this semester:
E-mail is a convenient tool to help us communicate. It is NOT, however, a free-for-all. You should be courteous when you e-mail your professors. Please write in complete sentences and in actual English; do not fill your message with SMS jargon or slang. If you don’t have time to write a respectable, readable message, you should not write it at all but seek some form of communication that fits your schedule.
1.) I have a question about the reading or about a writing issue.
2.) I do not understand what you said in class about a discussion topic.
3.) I cannot come to your office hours this week but would like to see you at a different time or arrange to talk to you on Skype.
4.) I will have to miss class next week and would like to arrange something.
5.) I have a scheduling problem or a conflict.
Inappropriate topics (I will ignore these messages)-
1.) Please tell me what you covered in the class I missed.
2.) What’s the homework?
3.) U have 2 (something something) 4 me.
4.) Imma gonna b goin 2 a gr8 fam vaca next week so u need 2 (something something) 4 me pronto.