No, use of CAPS LOCK in an semi-academic setting such as this site is not appropriate. Besides being hard to read, the most commonly understood intonation is that of shouting. I can think of very few contexts on this site where shouting is appropriate, usually either bold or italic text would give the desired emphasis. Most of the time people that use all-caps in writing prose do so either out of laziness or ignorance (either of how to format their text using markup of any kind or of what the standard intonations are for various markups). A comment letting them know they are, wittingly or unwittingly, in breach of Internet etiquette is usually all it takes to clear things up.
Feel free to edit out any instances of all-caps where shouting is not the obvious intended intonation provided there are either sufficient other changes that need to be made anyway or the usage is particularly egregious (e.g. whole sentences or paragraphs rather than just single words). There is rarely a post that can't use some other touch-up work anyway, but editing and bumping posts only to change a stray word or two is probably not such a good idea.