Like many other members here, I think it is better to be safe than be sorry later on. Furthermore, I especially disagree with vijay and some one else who said that they can make more friends by posting their pictures. Its sad that they have to use their face to make friends.
For one thing, you really cannot trust everyone who sees this website. Also, most internet crimes occur on fourms and by chatting. In my opinion putting your picture makes more target and attraction to oneself. These internet criminals tend to be the most persuading and friendly people online because I don't think that the people who have suffered were not stupid either to not realize that they were traps. But suppose someone really likes your looks and of course they are going to gain your trust to persuade u into what they want.
I am getting this opinion after the Middle East "internet murder" that appeared in BBC News in 2001 (link: http://news.bbc.co.uk/2/hi/middle_east/1189804.stm). Don't pretend the world is pretty and cheerful...itz a BIG BAD WORLD out there! Btw I'm sorry if I offended anyone.