"So what's driving the spammers then? According to Google, it's
partially due to the failure of spam-detection vendors.
""Whenever we see an unusual spike it's not always the case that
spammers have increased their volume arbitrarily," Raghavan argued.
"It is the case that a few vendors have been ineffective at
detecting the links. Once spammers figure that someone is not
detecting their technique really well, they pummel the
system.""
