“Dotted quad” spam makes a splashy return to this report as the volume more than tripled from the month prior. The most observed spam subject line of the month was also the dotted quad spam attack. With respect to message size, attachment spam continued to creep up in volume in March. This, along with an increase in NDR spam, raised the average message size. The 5kb – 10kb bucket increased by over four percentage points and the 10+kb bucket increased by over nine percentage points. With respect to spam categories, scam and phishing messages in April accounted for 17 percent of all spam, remaining unchanged compared to March. Overall, spam made up 89.22 percent of all messages in April, compared with 89.34 percent in March. Please download the May 2010 State of Spam & Phishing Report, which highlights the following trends: • Deeper Dive into Dotted Quad Spam • A Fake Fast Food Survey • UK Students Under Scam Attack • Another Holiday Spammers Can’t Skip On • April 2010: Spam Subject Line Analysis • Will the Trend Continue?