41. The apparatus in claim 37 wherein the processor, in response to the stored instructions: detects whether each of a first group of predefined handcrafted features exists in the incoming message so as to yield first output data; analyzes text in the incoming message so as to break the text into a plurality of constituent tokens; ascertains, using a word-oriented indexer and in response to said tokens, whether each of a second group of predefined word-oriented features exists in the incoming message so as to yield second output data, said first and second groups collectively defining an n-element feature space (where n is an integer greater than N); forms, in response to the first and second output data, an N-element feature vector which specifies whether each of said N features exists in the incoming message; and applies the feature vector as input to the probabilistic classifier so as to yield the output confidence level for the incoming message.
44. The apparatus in claim 41 wherein the message is an electronic mail (e-mail) message and said first and second classes are non-legitimate and legitimate messages, respectively.