Botnets went through a remarkable period of growth and change last year, Damballa study says. At its peak in 2010, the total number of unique botnet victims grew by 654 percent. Of the top 10 largest botnets, six did not exist in 2009, report says. Botnet operators now prefer to use networks primarily as a means of stealing data, expert says. The biggest botnet of 2010 — one associated with the TDL Gang — rose to international attention in the second half of the year.”]