I actually sometimes do use ":o" as a neutralizer of sorts when I fear my posts sound hostile or rhetorical when they aren't meant that way. :c
I read things differently when they have an emoticon, as I feel some others do. There is a difference to me. For example:
"Do you have a mental condition?" Can sound very rude in and out of context. However,
"Do you have a mental condition? :o" Just sounds like an honest question, and makes it sound like I'm actually asking it and not being rhetorical.
If that makes any sense. :s
Plus, I like the little faces. They're so cute. :3