Lately, I have been seeing scare quotes used frequently in both blogging and social media.
Although they can impart a sense of irony, they are usually used as a clever shorthand to indicate disbelief or disdain, often in a nasty way. (I am ashamed to say I have used them in this way.)
I am now of the opinion that if I disagree with someone or something, then I should either state it clearly or keep my thoughts to myself—preferably the latter. I don’t believe being grammatically sly is something I should strive for.