I've recently discovered there's a name for it. Unfortunately, there's no cure. It's the Argumentum ad CAPSLOCK. You've all seen this, whenever a religious fundamentalist or conspiracy theorist or general crank appears on a forum or in a comments list, they tend to EMPHASISE certain IMPORTANT words and PHRASES, in order to get their POINT across. As soon as you see it in a person's post, it's a sure-fire indication that they're a few sandwiches short of a picnic. Heck, even the few examples above are making my blog look unstable!
If you want a slew of examples of these phenomena - though why you would want to? - you should check out this website: www.crank.net . Be warned, there are a lot of disturbed people out there, and they've got computers.