My conversational things are filled with them ;~; About half my sentences usually have an emote in them, about half the time xD But D: . ;~; , c: , and x3 are particularly common. I shift at times though: at times I've used ^_^ , >_> , :3 , /o/ , :-: , and... well, lots super commonly. It's goooood though, since it means there's a lot less ambiguity in my tone and I don't feel there's anything wrong with reminding people you aren't out to kill them? Though it is admittedly weird if I, like, begin and end a sentence with the same emote (which isn't too uncommon).
And I guess yeah it probably looks a little immature. But I guess I hope my more serious posts have good enough content that it doesn't really matter? Iunno.