1. An article of manufacture comprising a program storage medium having computer readable code embodied therein, the computer readable code being configured for handling at least an email message received through a communication network, said email message including a target document, said target document involving an encoding scheme, the article of manufacture comprising: code for training, using a plurality of text document samples that have been encoded with different encoding schemes and selected for training purposes, said different encoding schemes pertaining to charset encoding for transmission over a network, to obtain a set of machine learning models, said training including using a SVM (Support Vector Machine) technique to generate said set of machine learning models from feature vectors converted from said plurality of text document samples, said feature vectors are grouped by charsets, wherein said training including generating fundamental units from said plurality of text document samples for charsets of said plurality of text document samples and extracting a subset of said fundamental units to form a set of feature lists, said feature vectors are converted from said set of feature lists and said plurality of text document samples, said extracting said subset of said fundamental units includes filtering said fundamental units to obtain fundamental units that are more discriminatory in describing differences among said different encoding schemes; code for applying said set of machine learning models against a set of target document feature vectors converted from said target document, said applying including analyzing said set of target document feature vectors using said set of machine learning models to compute similarity indicia between said set of target document feature vectors and said set of machine learning models associated with said different encoding schemes, wherein a first encoding scheme associated with said set of machine learning models is designated as said encoding scheme if characteristics of said first encoding scheme as represented by said set of machine learning models are computed to be most similar, relative to other encoding schemes of said different encoding schemes, to said set of target document feature vectors; code for decoding said target document to obtain decoded content of said target document based on at least said first encoding scheme; code for determining whether said email message is a spam message based on at least said decoded content of said document; and code for preventing said email message from reaching an email user if said email message is determined to be spam according to said determining.