"That annoys me to no end," says. "Sometimes, people have told me they get so annoyed with those that they'll un-follow a person."

Remember, many people have direct messages sent to their e-mail inboxes. In this case, you could increase their e-mail overload problem.

Also, remember what someone sends you via a direct message isn't for public consumption.

"There's an implied confidentiality there," Boyd says. "It wouldn't be good etiquette to post a direct message with someone's name on it unless you got permission."