Because I don't want Evil Spammers to get me. There are things called spambots, which are- in my very general knowledge- programmes that trawl webpages looking for complete email addresses which they then send spam to. You can "break" your email address easily so people can sent email to you but bots can't find it because they're not intelligent. As I understand it, although it would be good to get someone who actually understands the concept better (rather than merely putting it into practice as I do.)