EElyn writes "Numerous users of Blue Security's anti-spam system now report of a new form of aggressive spam. An unknown group of spammers claim to have derived a way to extract the member email addresses of Blue Security group's anti-spam system, called Blue Frog. Blue Frog, a small tool which once installed on the user's computer, enables Blue Security to systematically flood a known spammer's website with opt-out messages; much to the headache of the spammer. Tens of thousands of users have already signed up, so can it really be true that spammers now possess this database? Or is this yet another frail attempt by spammers to intimidate the user?" Another reader sent the text of the letter; read more to see.