Spam messages punting pornographic websites dropped in frequency to reach an all time low last month.

Adult spam represented only three per cent of the total amount of spam sent, while overall junk mail levels remained virtually unchanged, according to a study by net security firm Symantec.

Health, financial and product spam dominate the junk mail landscape with scam emails accounting for a mere eight per cent of junk mail traffic.

Symantec reckons 70 per cent of the total email volume in February was spam, a slight increase on previous months. Many of these spam messages (38 per cent) adopted the increasingly popular tactic of displaying spam messages in the form of images, a tactic designed to foil less sophisticated anti-spam software.

A separate study by email filtering firm MessageLabs, also covering February, paints a different picture of junk email trends. MessageLabs reckons the global ratio of spam in email traffic was 77.8 per cent (or one in 1.29 emails), an increase of two percentage points on previous months.

One in 203.7 (0.49 per cent) of emails sent in February involved some form of phishing attack. MessageLabs estimates 55.4 per cent of all malicious emails intercepted in February were phishing attacks, a decrease of 0.8 percentage points from January 2007. ®