message

Don't use message as a verb. Use send, receive, email, text, or send an IM instead.

Use email, message, or email message to refer to an item sent or received using email.

Use text or text message to refer to an item sent or received using SMS.

To refer to an item sent or received using instant messaging, spell out instant message on the first mention if your audience might not be familiar with the abbreviation. After that, it's OK to use IM.

See also
email
instant message, IM
text, text message