emoji seem to be very popular now;
my guess is that it's because they allow people to express themselves visually/gesturally/emotively
in a way that used to be excluded from digital conversations.
it probably also doesn't hurt that they're so cute.
(i would call them exemplars of the 'objet discret' aesthetic.)
if you'd like to decorate your own conversations with these characters
(including some more utilitarian symbols),
please feel free to hit the click-to-copy buttons below.