The volume of spam e-mails being sent across the world has witnessed a sharp decline since August 2010 and recorded the lowest during Christmas.

While the number was nearly 200 billion spam messages each day in August, it shrunk to 50 billion in December, according to BBC News.

Symantec Hosted Services senior analyst Paul Wood was quoted by BBC as saying that the sudden drop during Christmas is because three of the largest spam producers cut down their spamming activity.

"Most spam is generated by botnets which are networks of infected computers. Botnet Rustock was at its peak responsible for between nearly 47% of global spam," Wood added.

In December, it managed to generate just 0.5% of global spam.

The drop in spam could be because the spammers are simply regrouping ahead of a new campaign.

Web security firm Websense researcher Carl Leonard told the BBC that it could also be because spammers are considering other communication formats such as social networking site Facebook and microblogging service Twitter instead of just considering e-mails.