for some people, this might be just a symbol. but for me, this is something meaningful that could represent someone's smile that i cant see right through my own eyes, because they're so far away.. it might be silly, but for me, reading a message no matter where it came from, sms, emails, twitter mentions, facebook walls or even chat and others, it shows that someone over there is appreciating their message to me and really mean it.
it's not only a symbol, but its a feeling that you're sharing your happiness with others through it. lets share!
"give someone your smile today, it might be the only smile that they get for the rest of their day"