Spam decreased 8 percent during September, according to a report (PDF) released Monday by MessageLabs.
Among other reasons behind the decrease, the security company cited the apparent demise of California-based Intercage, an Internet service provider alleged to have possibly been used to host command and control servers for various . Intercage's upstream provider, Pacific Internet Exchange, terminated service on September 20; a second upstream provider, UnitedLayer, then terminated service on September 25. During this period, MessageLabs reported a marked decrease in spam traffic.
Looking deeper into the spam traffic itself, MessageLabs found that 85 percent of sexually explicit e-mail spam is sent during the workday. A healthy 28 percent of that is sent during the lunch hours, from 11 a.m. to 1 p.m. local time. Almost all of this is blocked by corporate filters.