Sarcasm shouldn't stick out at first, because half the reason for sarcasm's being enjoyable is the feeling when you "get it" without any help. I was playing around with making <sarcasm> render normally, but with a little grey square at the end of a sarcasm block, inline with the rest of the text, which, when you hover over it, higlights the text pink if it actually was sarcasm. There would also be <seriously>, which would have the same grey square, but wouldn't light up. in order for sarcasm to still get laughs/amused grins, <sarcasm> and <seriously> would have to be used in roughly equal amounts, so you'd never be able to accidentally scan ahead to realize which one you have.