I just received this from a hosting company....

PHP Nuke Sites are currently being exploited and used to send massive amounts of spam email with illegal phishing content plus much more. If they are not patched properly and the mail feature is turned on within PHP Nuke the hackers/spammers will exploit your PHP Nuke Installs to send massive email amounts at your expense. Please make sure PHP Nuke is updated to the latest version if you are using it as for this will result in your site being terminated /suspended if it is reported for spamming via their PHP Nuke Portal. PHP Nuke is very vulnerable. We would recommend to switch to a different Content management system such as Mambo. Please be sure to relay the message to all your clients (if any) that they MUST update their PHP Nuke Sites to the latest revision of PHP Nuke and run all the patches if they wish to continue to use PHP Nuke on our Network....


So, your website can now be sending out spam without your knowledge and your email address can be being blacklisted throughout the net as you are reading this. I don't have any PHP Nuke sites but if you do it may be worthwile to pay attention to this.