I also used one once in a chat with someone... I had to take it back. It felt /wrong/.
Unless, of course, you use, like, ten thousand. Then it gets your point across quite well be it mockery, excitement, or GTFO PISSED. But I remember when we used to make fun of people for abusing them. Caps as well, though that was a dark spot in my history. Caps are lovely. ^.^