Sophos experts believe that a possible reason for America's increasing lead in relayed spam when compared to its closest rival, China, is the emergence of over 300 strains of the mass-spammed Stratio worm. The worm, also known as Stration or Warezov, uses a trick dependent on the victim being able to speak English in its attempt to convert innocent PCs into members of a spam botnet.

1 United States 21.6%
2 China (incl Hong Kong) 13.4%
3 France 6.3%
3 South Korea 6.3%
5 Spain 5.8%
6 Poland 4.8%
7 Brazil 4.7%
8 Italy 4.3%
9 Germany 3.0%
10 Taiwan 2.0%
11 Israel 1.8%
12 Japan 1.7%

Others 24.3%

Elsewhere in the chart, China has managed to decrease the proportion of spam it relays by 6.6% since last quarter. The UK has successfully dropped out of the chart altogether and is currently in 13th position, while Israel has entered for the first time, taking 11th place. Q3 has also seen spammers deploy new tricks (image spam) to try and fool both users and anti-spam software.