The total volume of spam hitting our collective inboxes continues to decline. According to the latest data from Symantec, the global spam volume in October declined by 22% month-over-month and over 47% since August. This reduction can be attributed to the shutdown of major spam networks like and the Bredolab botnet. Even with this decline, though, spam still made up 86.6% of all emails in October. This is the lowest number Symantec has reported since September 2009.

As The Register’s John Leyden notes, Symantec’s numbers fall in line with similar data from Kaspersky Lab, which reported that spam dropped to 82.3% in the third quarter of 2010.

Dutch authorities took down several servers associated with the Bredolab botnet at the end of October (though there is some evidence that this botnet is still active). Symantec cites this, as well as the takedown of the Zeus ring and, as the main reasons for this decline in total spam volume.

Phishing on Social Media on the Rise

While, according to Symantec, phishing scams on social media sites only comprised about 4% of all phishing attacks, the total number of phishing sites on social media increased by about 80% compared to last month. The security firm also notes that one of the most popular phishing scams in October involved emails and messages that claimed to come from a social media site’s security service and asked users for their login credentials. These scams told consumers that they had to reenter their credentials (on a phishing site, of course) to ensure continued access to the service.