Fortinet also noted that the global volume of spam in December jumped nearly 11 per cent from November, as spammers regained their footing after the takedown of McColo. McColo was a Web hosting firm responsible for hosting a substantial proportion of the world's malware and botnet operators. The company ceased operations in November after two Internet providers cut off the firm's connectivity to the Web.

Spam topics during the year-end period 'took advantage of the holiday season and failing economy', according to Fortinet. Popular subject lines concerned electronic greeting cards, an undeliverable UPS package notification and a home loan modification scheme.