Reshef, Eran (contributor); Solan, Eilon (contributor) - 2005
cost of mailing spam messages, on the total number of messages that spammers send. We show that increasing the cost of … mailing spam messages have the unequivocal effect of reducing the total number of spam messages sent by spammers. On the other … hand, improving the quality of the filters have an ambiguous effect: users who uses the improved filter receive less spam …