Lisa M. Bates, an assistant professor of epidemiology at Columbia, has lately embraced the smiley — as have her academic colleagues, albeit “sparingly and strategically,” she said. “Basically, I’m often sarcastic and in a hurry, and a well-planted smiley face can take the edge off and avoid misunderstanding,” Dr. Bates wrote in an e-mail. “I figure they have saved me some grief from misconstrued tone many times.”

Emoticons can produce another layer of confusion, however: they don’t always read the same way across different technical interfaces. “In the text function of my BlackBerry there is a sidebar menu of emoticons (how ridiculous is that?) that shows the yellow smiley faces, except they are also crying and raging, and winking and blowing kisses, etc.,” Dr. Bates wrote. “I sent a fairly new acquaintance a ‘big hug’ emoticon — which, for the record, was ironic. But anyway, on his iPhone it came up with the symbols, not the smiley face, which don’t look anything like a big hug. From his perspective they look like a view of, er, splayed lady parts: ({}).“He then ran around his lab showing colleagues excitedly what I had just sent him. Half (mostly men) concurred with his interpretation, and the others (mostly women) didn’t and probably thought he was kind of a desperate perv.”

These little misinterpretations aside, recent adoptees like Dr. Bates and Ms. Heller said that emoticons not only signal intention in a medium where it’s notoriously hard to read tone, they also denote a special congenial relationship between sender and recipient. “I see it as a relationship-building exercise,” Ms. Heller said.

Students of digital communication see the emerging acceptance of whimsical signifiers as inevitable, if not always desirable. “They’re part of the degradation of writing skills — grammar, syntax, sentence structure, even penmanship — that come with digital technology,” said Bill Lancaster, a lecturer in communications at Northeastern University in Boston. “Certainly I understand the need for clarity. But language, used properly, is clear on its own.”

Perhaps it’s no surprise, then, that writers and teachers of writing are among the last emoticon holdouts. “I am deeply offended by them,” said Maria McErlane, a British journalist, actress and radio personality on BBC Radio 2. “If anybody on Facebook sends me a message with a little smiley-frowny face or a little sunshine with glasses on them, I will de-friend them. I also de-friend for OMG and LOL. They get no second chance. I find it lazy. Are your words not enough? To use a little picture with sunglasses on it to let you know how you’re feeling is beyond ridiculous.”