These days when speaking to people by texting on our cell phone or using the internet, there are many symbols used to say good bye and hello. I think most of us know that xxxx's and oooo's mean kisses and hugs, knowing which is which is another thing. To make sure we're all on the same page, here is a key for some of the common symbols used to express affection today.
ooo = hugs
xxx = kisses
OOO = big hugs
XXX = big kisses
oo = hugs for everybody but you
OO! = big, excited hugs
CCC = hugs for people you can't quite reach around
OOQ = hugging with tongue
xx@ = kisses and earlobe nibbling
zzz = snoring
yyy = anything that occurs between kissing and snoring"
http://www.netfunny.com/rhf/jokes/90q4/hugsf.html
One theory of how the X became the symbol for kiss is looking back to the way of people in the Medieval times. Back then, illiterate people would sign documents with a cross to show their sincerity and then to seal the deal, this cross was kissed. People hurried the t signature, so the cross would often end up looking like an X. And also back in the day, Jewish people signed their documents with an O. Now it is used as a symbol of arms embracing.