Periods—as of recently—have attitude.  Examine the following two hypothetical text messages:

“I’ll be home at 6”

and

“I’ll be home at 6.”

Which one would make you more nervous about the sender’s mood?

I think we would all agree that the primary importance of language is to convey meaning.  But language itself isn’t enough.  Texting limits one’s ability to convey intent.  While in-person one can read facial expressions and tone, the phone only shows words.  Additionally, texts are brief.  When a lot of texts are only one sentence or phrase, periods become superfluous.

These forces combined to give the period its unique textual meaning.  This isn’t just a coincidence though.  The ending period offers a sense of finality.  I can’t help but think back to the debate over Obama’s campaign slogan “Forward.”  How can we move forward if the period stops us in our tracks?

Ending without a period or with an ellipse (…) invites more of a response.  It provides less closure and finality, allowing the conversation to move forward.  Conversation is a unique and powerful method of communication.  It is no wonder that texting has attempted to mimic its helpful features.

For a more complete analysis of this phenomenon, check out this article from the New Republic.