I use a visible watermark signature that touches on parts of the image in ways that make it a pain to remove easily (it can be done, but it'll discourage the lazy and unskilled). I try to make it unobtrusive but still noticible. My particular watermark/signature is my nick and a little copyright symbol. bonni

"When a man gives his opinion, he's a man. When a woman gives her opinion, she's a bitch." - Bette Davis