There is disclosed a system and method for delivering a message to a communication device. In an embodiment, the method comprises obtaining a probability that the message is spam; in dependence upon the probability that the message is spam, determining a variable message size; and sending the message to the communication device in dependence upon the determined variable message size. In an embodiment, the method further comprises receiving a user response whether the message is spam; and if the message is verified as being spam, then filtering the message from the communication device.