Ananova:

The :-) computer smiley symbol celebrates its 25th birthday today.

The sideways face used in billions of emails was invented by an IT expert in Pittsburgh, US, reports The Sun.

Prof Scott Fahlman was the first to use a colon followed by a hyphen and a close bracket to form a smiley in a computer message.

It has since spawned dozens of similar characters, including the wink ;-) sad face :-( yawn :-O and surprise 8-O.

Prof Fahlman said he prefers :-) to the modern computer graphic of a smiling face, adding: "It destroys the whimsical element of the original."