Antispam Approaches
Researchers have developed various computational approaches-in particular, data mining methods-to detect email spam, and some have achieved a certain degree of success. Content-based approaches3 were among the first to be applied. In email spam filtering, for example, such methods consider content-based features that can be used for classification. A spam email often contains some indicative keywords, such as “free” or “awards,” or unusual distribution of punctuation marks and capital letters, such as “BUY!!” or “MONEY,”4 such that these keywords become important features that a machine-learning-based classification algorithm can use.