Web services anti abuse system
A huge issue for web applications is the constantly increasing 'web application abuse'. Web application abuse is typically performed by misusing interactive services like dynamic forms, forums, blogs, mail page modules, mailing registration systems, login systems, etc; basically any service that contains input characteristics is 'abuse-able'. Most abuse is 'just annoying', but some types can be very serious as well.
The abuse is commonly performed by hacked/infected home and personal computers, without the owners knowing this is happening (the real 'abusers' basically stay out of reach). Most abuse is performed for sending or posting spam, filling databases with spam or for redirecting internet users to spam or scam.
The xsdot anti-abuse framework contains 18 unique filters and functions to identify and block abusers. The framework works on a global per server basis and on a per service level (different services implement different abuse filter algorithms depending on the service nature).