On the whole, spam levels declined 12% from Q4-2009 to Q1-2010. However, during March 2010, Google observed that the average volume of spam increased 30%. This increase in spam has been attributed to the rise in image spam that prevailed during the Q2-2009 upsurge as well.

According to Senior Product Marketing Manager Adam Swidler with the Google Postini Team, an interesting thing noticed is that spam levels fell substantially, while such a fall in a single quarter isn't found often, as reported by SCmagazineUS.com on April 14, 2010.

Moreover, the report statistics suggest that although the levels of spam declined, the total worldwide spam volumes haven't changed during Q1-2010, in spite of leading botnets namely Zeus, Mariposa and Waledac being shutdown.

Furthermore, according to Swidler, this shows that the number of botnets isn't constrained in supply for spammers to carry on with their activities.

He adds that despite the various ISP takedowns as well as that of a few botnets, there's still a 6% year-on-year growth observed.

Swidler also says that one thing is therefore evident that during the period of ISP closures, spammers were reconstructing their other networks to recover losses. With that, Postini believes that the criminals were effectively launching computer virus assaults for expanding their botnets so that they could return to a situation in which there were readily available sources of spam distribution.

Gopal Shah, another member of Google Postini Team, posted on the blog that in 2010, more botnets are expected to be taken offline. However, still, the question is that if such takedowns would make a considerable effect on the overall amount of spam in the long run. Up till now during 2010, the impact has not been much, requiring the security industry to adopt additional measures so that they can bring about a greater 'increased' effect on worldwide levels of spam, Shah added, as reported by SCMagazineUS.com on April 14, 2010.