According to Kaspersky Lab, which compiles the monthly reports, the dramatic drop of the US in the spam origination stakes is largely due to the country's anti-botnet campaign.
The Russian IT security vendor also says that spammers distributing pharmaceutical spam from the US have realised that their activity will not continue to go unpunished and have switched to other partner programs.
This, says Kaspersky, is evident from the very small share of this type of spam registered throughout November: at the beginning of the month it was around the 40% mark, and by the end of the month it accounted for less than a third of all spam traffic.
Marie Namestnikova, the IT security software vendor's senior spam analyst, said that pharmaceutical spam remains a very profitable business, which is why it was so widespread on the internet until quite recently.
"Having lost part of their income from pharmaceutical spam, spammers from the USA and other countries are currently seeking out new opportunities to make money", she explained.
Namestnikova's report notes that, also during November, PayPal was the target of the most phishing attempts. Facebook also remained a popular target for phishers as the social networking site was targeted twice as often in November.
The report adds that the interest shown by phishers in eBay increased threefold compared with October's figure.
The focus of November's phishing attacks, says Kaspersky, was wider than the previous month. MasterCard and Visa cardholders were also targeted more often in November, whilst attacks on Visa Delta (debit card) cardholders also resumed.