Spam's slice of the e-mail pie has dropped by 12 percent so far this year, indicating that defensive strategies and technologies, and perhaps high-profile prosecutions of big-time spammers are having an affect, a message filtering firm announced Thursday.

Through August 2005, said Denver-based MX Logic, spam accounted for an average of 67 percent of the messages run through the company's filters. At the same point in 2004, spam accounted for an average of 76 percent of all mail.

"The drop in spam volume could indicate that improved e-mail defense technology and high-profile prosecutions of spammers might be having some effect," said Scott Chasin, MX Logic's chief technology officer, in a statement. "However, I would caution that these numbers only indicate that less junk may be reaching inboxes."

Raw counts of spam continue to climb, Chasin said, largely fueled by spam zombies, which he claimed send almost half -- 48 percent -- of all spam. "Until we get rid of spam zombies, we won't see any meaningful decline in spam or other Internet pollution," said Chasin.

"The overall volume of spam carried on the Internet continues to increase."

MX Logic also noted that the federal anti-spam law, the CAN-SPAM Act, which went into effect January 1, 2004, had little impact on junk mail: during August, only 3 percent of the 40,000 randomly-selected spam messages which MX Logic examined met the law's regulations. From January to July, 2005, the average was slightly higher; 4 percent.