Really? Someone mentions how sad they are over the death of their father, someone who meant so much to them, and your response is a sad-faced emoticon? You can't even take the time to type "so sorry?"
I envision a day when we will only communicate through emoticons, a day when they will act like our typographical moodrings to quickly let everyone know how we feel. Orwell was too optimistic when he wrote about language being reduced to "double-plus good" in 1984. On the other hand, perhaps the depth of your feelings can be summed up by a colon and a parenthesis.