Interoffice mail, whether electronic or traditional, always needs to be handled professionally, punctually and in a straightforward manner. Any response should be formal and involve common etiquette devices such as a subject line, a greeting and a salutation. Under no circumstance should interoffice mail involve offensive jokes, shorthand phrases such as "LOL" and "OMG" or potentially confidential information.
Similar to outgoing external mail, interoffice mail needs to involve professional language and subjects. Communication reflects on a person's professionalism, so proper tone and good grammar need to be used in all interoffice communications. Respectful, direct responses and questions should be part of any interoffice communication. Informal slang not only reflects poorly on the writer, it also affects the quality of the response. It is best to treat interoffice email with the same professionalism as mail that goes outside the office.
Most interoffice mail is short and time sensitive. It is a good practice to reply to emails, messages and letters in a timely manner -- usually within the same day. Responses should be brief and to the point. When writing an interoffice message, an informative subject line is key. This lets the recipient know the purpose for the message in the event they need to return to it later. It also tells them if it is a pressing matter that requires immediate attention.