Many spamming programs are wising up to the relatively simple tricks that people use to make their email address visible to human users but invalid to electronic systems.
The most common one is
[email protected] this no longer works- a good one is to alter spellings of your domain names, and put a note to that effect in your signature.
e.g.:
[email protected] Kingdom
Annotating it with 'remove all the dashes to email, and change the last bit to 'uk'.
However this may cause a problem with PPRuNe as passwords are sent electronically whenever you change the email address you are registrered under.