What's the meaning of a text message consisting only of a dot? [closed]
In manga dot's are used to express a silent response. This is needed because manga doesn't have time, it has panels. To show time passing without anything being said they put in dots.
If I send you a single dot in an SMS or chat it means, I'm here. I'm reading. I'm not saying anything. Because if I didn't for all you know I'm asleep.
In Kurt Vonnegut's absurdist/science fiction novel, The Sirens of Titan, the entire purpose of the evolution of the human race was to produce and deliver a small replacement part to a moon-stranded spaceship so it could complete its mission of carrying a message from one side of the universe to the other.
"The message consists of a single dot, which in the Tralfamadorian language means 'greetings.'"
See: http://webdoc.sub.gwdg.de/edoc/ia/eese/artic99/klein2/5_99.html
Also see: https://en.wikipedia.org/wiki/The_Sirens_of_Titan
Depending on the context of course, a single . can signify sorrow and commiseration.
Person 1: My cat died today
Person 2: .
Person 3: I'm sorry for your loss.
It can be a simple way of paying respects, or a "moment of silence".
Example and further explanation.