John, the answer is never let your email address appear on a webpage - easier said than done, I know, but there are ways round it:

- use disposable addresses - I have a Yahoo account and they let me set up any number of disposable addresses of the form

[your-prefix]-[anything-you-want]@yahoo.co.uk

if one of them starts getting spammed, you just throw it away.

- if you want to publish your address on a website, use some means of hiding it eg a bit of JavaScript. I had a bit of a bust-up with the BMIC (British Music Information Centre) because they publish email addresses in an unencrypted form on their website - including one of mine (without my permission), which then started receiving large amounts of spam. I asked them to remove the address, which they did, but someone then put it back on their site - leading to a really annoyed email to them from me. I've now had to ditch that email address, almost entirely due to the BMIC publishing it.

<end of rant>