In the early days of email, people quickly discovered the limitations of a textual medium to convey very personal, emotional thoughts. To try to provide shortcuts to emotional language, smileys were born. Intended to be “read” sideways-on, they provided a substitute for facial expression, albeit in a very primitive fashion.
Emoticons or smileys express emotion:
Example 3.1. A few emoticons (or smileys)
:-)
happy
:-(
sad
;^)
tongue-in-cheek
:-P
tongue sticking out
:-O
surprised (open
mouthed)
%-\
a pretty bad hangover
There's a canonical list of well used smileys, and an exhaustive Emoji list of every possible combination of features.
Acronyms and abbreviations abound, particularly in chat programs and virtual worlds. Here are a few...
Example 3.2. Commonly used email abbreviations
LOL
laughs out loud
IMHO
in my humble opinion
BTW
by the way
RTFM
read the flippin'
manual!
<g>
grin
There are a number of lists of these acronyms and abbreviations, such as the one at NetLingo, and there's even an acronym server